26 files changed, 333 insertions, 155 deletions

diff --git a/client/src/app/+accounts/account-video-channels/account-video-channels.component.html b/client/src/app/+accounts/account-video-channels/account-video-channels.component.html
index 379c0443e..34dc52029 100644
--- a/client/src/app/+accounts/account-video-channels/account-video-channels.component.html
+++ b/client/src/app/+accounts/account-video-channels/account-video-channels.component.html
@@ -23,10 +23,10 @@
         </h2>
 
         <div class="actor-counters">
-          <div class="followers" i18n>{videoChannel.followersCount, plural, =1 {1 subscriber} other {{{ videoChannel.followersCount }} subscribers}}</div>
+          <div class="followers" i18n>{videoChannel.followersCount, plural, =0 {No subscribers} =1 {1 subscriber} other {{{ videoChannel.followersCount }} subscribers}}</div>
 
           <span class="videos-count" *ngIf="getTotalVideosOf(videoChannel) !== undefined" i18n>
-            {getTotalVideosOf(videoChannel), plural, =1 {1 videos} other {{{ getTotalVideosOf(videoChannel) }} videos}}
+            {getTotalVideosOf(videoChannel), plural, =0 {No videos} =1 {1 video} other {{{ getTotalVideosOf(videoChannel) }} videos}}
           </span>
         </div>
 
diff --git a/client/src/app/+accounts/accounts.component.html b/client/src/app/+accounts/accounts.component.html
index 8362e6b7e..e235d9689 100644
--- a/client/src/app/+accounts/accounts.component.html
+++ b/client/src/app/+accounts/accounts.component.html
@@ -33,10 +33,10 @@
             </div>
 
             <div class="actor-counters">
-              <span i18n>{naiveAggregatedSubscribers(), plural, =1 {1 subscriber} other {{{ naiveAggregatedSubscribers() }} subscribers}}</span>
+              <span i18n>{naiveAggregatedSubscribers(), plural, =0 {No subscribers} =1 {1 subscriber} other {{{ naiveAggregatedSubscribers() }} subscribers}}</span>
 
               <span class="videos-count" *ngIf="accountVideosCount !== undefined" i18n>
-                {accountVideosCount, plural, =1 {1 videos} other {{{ accountVideosCount }} videos}}
+                {accountVideosCount, plural, =0 {No videos} =1 {1 video} other {{{ accountVideosCount }} videos}}
               </span>
             </div>
           </div>
diff --git a/client/src/app/+accounts/accounts.component.ts b/client/src/app/+accounts/accounts.component.ts
index 898325492..cf66b817a 100644
--- a/client/src/app/+accounts/accounts.component.ts
+++ b/client/src/app/+accounts/accounts.component.ts
@@ -30,8 +30,6 @@ export class AccountsComponent implements OnInit, OnDestroy {
   links: ListOverflowItem[] = []
   hideMenu = false
 
-  accountFollowerTitle = ''
-
   accountVideosCount: number
   accountDescriptionHTML = ''
   accountDescriptionExpanded = false
@@ -121,12 +119,6 @@ export class AccountsComponent implements OnInit, OnDestroy {
     this.notifier.success($localize`Username copied`)
   }
 
-  subscribersDisplayFor (count: number) {
-    if (count === 1) return $localize`1 subscriber`
-
-    return $localize`${count} subscribers`
-  }
-
   searchChanged (search: string) {
     const queryParams = { search }
 
@@ -150,8 +142,6 @@ export class AccountsComponent implements OnInit, OnDestroy {
   }
 
   private async onAccount (account: Account) {
-    this.accountFollowerTitle = $localize`${account.followersCount} direct account followers`
-
     this.accountDescriptionHTML = await this.markdown.textMarkdownToHTML(account.description)
 
     // After the markdown renderer to avoid layout changes
diff --git a/client/src/app/+admin/config/edit-custom-config/edit-configuration.service.ts b/client/src/app/+admin/config/edit-custom-config/edit-configuration.service.ts
index 9b55cb43c..96f5b830e 100644
--- a/client/src/app/+admin/config/edit-custom-config/edit-configuration.service.ts
+++ b/client/src/app/+admin/config/edit-custom-config/edit-configuration.service.ts
@@ -1,5 +1,6 @@
 import { Injectable } from '@angular/core'
 import { FormGroup } from '@angular/forms'
+import { prepareIcu } from '@app/helpers'
 
 export type ResolutionOption = {
   id: string
@@ -86,9 +87,10 @@ export class EditConfigurationService {
     return {
       value,
       atMost: noneOnAuto, // auto switches everything to a least estimation since ffmpeg will take as many threads as possible
-      unit: value > 1
-        ? $localize`threads`
-        : $localize`thread`
+      unit: prepareIcu($localize`{value, plural, =1 {thread} other {threads}}`)(
+        { value },
+        $localize`threads`
+      )
     }
   }
 }
diff --git a/client/src/app/+admin/follows/following-list/follow-modal.component.ts b/client/src/app/+admin/follows/following-list/follow-modal.component.ts
index c40b36e10..bac7b2b01 100644
--- a/client/src/app/+admin/follows/following-list/follow-modal.component.ts
+++ b/client/src/app/+admin/follows/following-list/follow-modal.component.ts
@@ -1,5 +1,6 @@
 import { Component, EventEmitter, OnInit, Output, ViewChild } from '@angular/core'
 import { Notifier } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { splitAndGetNotEmpty, UNIQUE_HOSTS_OR_HANDLE_VALIDATOR } from '@app/shared/form-validators/host-validators'
 import { FormReactive, FormValidatorService } from '@app/shared/shared-forms'
 import { InstanceFollowService } from '@app/shared/shared-instance'
@@ -60,7 +61,13 @@ export class FollowModalComponent extends FormReactive implements OnInit {
     this.followService.follow(hostsOrHandles)
       .subscribe({
         next: () => {
-          this.notifier.success($localize`Follow request(s) sent!`)
+          this.notifier.success(
+            prepareIcu($localize`{count, plural, =1 {Follow request} other {Follow requests}} sent!`)(
+              { count: hostsOrHandles.length },
+              $localize`Follow request(s) sent!`
+            )
+          )
+
           this.newFollow.emit()
         },
 
diff --git a/client/src/app/+admin/overview/comments/video-comment-list.component.ts b/client/src/app/+admin/overview/comments/video-comment-list.component.ts
index f3f43a900..f1b27d846 100644
--- a/client/src/app/+admin/overview/comments/video-comment-list.component.ts
+++ b/client/src/app/+admin/overview/comments/video-comment-list.component.ts
@@ -7,6 +7,7 @@ import { DropdownAction } from '@app/shared/shared-main'
 import { BulkService } from '@app/shared/shared-moderation'
 import { VideoCommentAdmin, VideoCommentService } from '@app/shared/shared-video-comment'
 import { FeedFormat, UserRight } from '@shared/models'
+import { prepareIcu } from '@app/helpers'
 
 @Component({
   selector: 'my-video-comment-list',
@@ -145,7 +146,13 @@ export class VideoCommentListComponent extends RestTable implements OnInit {
     this.videoCommentService.deleteVideoComments(commentArgs)
       .subscribe({
         next: () => {
-          this.notifier.success($localize`${commentArgs.length} comments deleted.`)
+          this.notifier.success(
+            prepareIcu($localize`{count, plural, =1 {1 comment} other {{count} comments}} deleted.`)(
+              { count: commentArgs.length },
+              $localize`${commentArgs.length} comment(s) deleted.`
+            )
+          )
+
           this.reloadData()
         },
 
diff --git a/client/src/app/+admin/overview/users/user-list/user-list.component.ts b/client/src/app/+admin/overview/users/user-list/user-list.component.ts
index 9d11bd02e..f7dc22256 100644
--- a/client/src/app/+admin/overview/users/user-list/user-list.component.ts
+++ b/client/src/app/+admin/overview/users/user-list/user-list.component.ts
@@ -2,7 +2,7 @@ import { SortMeta } from 'primeng/api'
 import { Component, OnInit, ViewChild } from '@angular/core'
 import { ActivatedRoute, Router } from '@angular/router'
 import { AuthService, ConfirmService, LocalStorageService, Notifier, RestPagination, RestTable, ServerService } from '@app/core'
-import { getAPIHost } from '@app/helpers'
+import { prepareIcu, getAPIHost } from '@app/helpers'
 import { AdvancedInputFilter } from '@app/shared/shared-forms'
 import { Actor, DropdownAction } from '@app/shared/shared-main'
 import { AccountMutedStatus, BlocklistService, UserBanModalComponent, UserModerationDisplayType } from '@app/shared/shared-moderation'
@@ -209,13 +209,25 @@ export class UserListComponent extends RestTable implements OnInit {
   }
 
   async unbanUsers (users: User[]) {
-    const res = await this.confirmService.confirm($localize`Do you really want to unban ${users.length} users?`, $localize`Unban`)
+    const res = await this.confirmService.confirm(
+      prepareIcu($localize`Do you really want to unban {count, plural, =1 {1 user} other {{count} users}}?`)(
+        { count: users.length },
+        $localize`Do you really want to unban ${users.length} users?`
+      ),
+      $localize`Unban`
+    )
+
     if (res === false) return
 
     this.userAdminService.unbanUsers(users)
         .subscribe({
           next: () => {
-            this.notifier.success($localize`${users.length} users unbanned.`)
+            this.notifier.success(
+              prepareIcu($localize`{count, plural, =1 {1 user} other {{count} users}} unbanned.`)(
+                { count: users.length },
+                $localize`${users.length} users unbanned.`
+              )
+            )
             this.reloadData()
           },
 
@@ -224,21 +236,28 @@ export class UserListComponent extends RestTable implements OnInit {
   }
 
   async removeUsers (users: User[]) {
-    for (const user of users) {
-      if (user.username === 'root') {
-        this.notifier.error($localize`You cannot delete root.`)
-        return
-      }
+    if (users.some(u => u.username === 'root')) {
+      this.notifier.error($localize`You cannot delete root.`)
+      return
     }
 
-    const message = $localize`If you remove these users, you will not be able to create others with the same username!`
+    const message = $localize`<p>You can't create users or channels with a username that already used by a deleted user/channel.</p>` +
+      $localize`It means the following usernames will be permanently deleted and cannot be recovered:` +
+      '<ul>' + users.map(u => '<li>' + u.username + '</li>').join('') + '</ul>'
+
     const res = await this.confirmService.confirm(message, $localize`Delete`)
     if (res === false) return
 
     this.userAdminService.removeUser(users)
       .subscribe({
         next: () => {
-          this.notifier.success($localize`${users.length} users deleted.`)
+          this.notifier.success(
+            prepareIcu($localize`{count, plural, =1 {1 user} other {{count} users}} deleted.`)(
+              { count: users.length },
+              $localize`${users.length} users deleted.`
+            )
+          )
+
           this.reloadData()
         },
 
@@ -250,7 +269,13 @@ export class UserListComponent extends RestTable implements OnInit {
     this.userAdminService.updateUsers(users, { emailVerified: true })
       .subscribe({
         next: () => {
-          this.notifier.success($localize`${users.length} users email set as verified.`)
+          this.notifier.success(
+            prepareIcu($localize`{count, plural, =1 {1 user} other {{count} users}} email set as verified.`)(
+              { count: users.length },
+              $localize`${users.length} users email set as verified.`
+            )
+          )
+
           this.reloadData()
         },
 
diff --git a/client/src/app/+admin/overview/videos/video-list.component.ts b/client/src/app/+admin/overview/videos/video-list.component.ts
index 82ff372aa..67e52d100 100644
--- a/client/src/app/+admin/overview/videos/video-list.component.ts
+++ b/client/src/app/+admin/overview/videos/video-list.component.ts
@@ -3,6 +3,7 @@ import { finalize } from 'rxjs/operators'
 import { Component, OnInit, ViewChild } from '@angular/core'
 import { ActivatedRoute, Router } from '@angular/router'
 import { AuthService, ConfirmService, Notifier, RestPagination, RestTable } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { AdvancedInputFilter } from '@app/shared/shared-forms'
 import { DropdownAction, Video, VideoService } from '@app/shared/shared-main'
 import { VideoBlockComponent, VideoBlockService } from '@app/shared/shared-moderation'
@@ -196,14 +197,24 @@ export class VideoListComponent extends RestTable implements OnInit {
   }
 
   private async removeVideos (videos: Video[]) {
-    const message = $localize`Are you sure you want to delete these ${videos.length} videos?`
+    const message = prepareIcu($localize`Are you sure you want to delete {count, plural, =1 {this video} other {these {count} videos}}?`)(
+      { count: videos.length },
+      $localize`Are you sure you want to delete these ${videos.length} videos?`
+    )
+
     const res = await this.confirmService.confirm(message, $localize`Delete`)
     if (res === false) return
 
     this.videoService.removeVideo(videos.map(v => v.id))
       .subscribe({
         next: () => {
-          this.notifier.success($localize`Deleted ${videos.length} videos.`)
+          this.notifier.success(
+            prepareIcu($localize`Deleted {count, plural, =1 {1 video} other {{count} videos}}.`)(
+              { count: videos.length },
+              $localize`Deleted ${videos.length} videos.`
+            )
+          )
+
           this.reloadData()
         },
 
@@ -215,7 +226,13 @@ export class VideoListComponent extends RestTable implements OnInit {
     this.videoBlockService.unblockVideo(videos.map(v => v.id))
       .subscribe({
         next: () => {
-          this.notifier.success($localize`Unblocked ${videos.length} videos.`)
+          this.notifier.success(
+            prepareIcu($localize`Unblocked {count, plural, =1 {1 video} other {{count} videos}}.`)(
+              { count: videos.length },
+              $localize`Unblocked ${videos.length} videos.`
+            )
+          )
+
           this.reloadData()
         },
 
@@ -224,9 +241,21 @@ export class VideoListComponent extends RestTable implements OnInit {
   }
 
   private async removeVideoFiles (videos: Video[], type: 'hls' | 'webtorrent') {
-    const message = type === 'hls'
-      ? $localize`Are you sure you want to delete ${videos.length} HLS streaming playlists?`
-      : $localize`Are you sure you want to delete WebTorrent files of ${videos.length} videos?`
+    let message: string
+
+    if (type === 'hls') {
+      // eslint-disable-next-line max-len
+      message = prepareIcu($localize`Are you sure you want to delete {count, plural, =1 {1 HLS streaming playlist} other {{count} HLS streaming playlists}}?`)(
+        { count: videos.length },
+        $localize`Are you sure you want to delete ${videos.length} HLS streaming playlists?`
+      )
+    } else {
+      // eslint-disable-next-line max-len
+      message = prepareIcu($localize`Are you sure you want to delete WebTorrent files of {count, plural, =1 {1 video} other {{count} videos}}?`)(
+        { count: videos.length },
+        $localize`Are you sure you want to delete WebTorrent files of ${videos.length} videos?`
+      )
+    }
 
     const res = await this.confirmService.confirm(message, $localize`Delete`)
     if (res === false) return
diff --git a/client/src/app/+my-account/my-account-settings/my-account-notification-preferences/my-account-notification-preferences.component.ts b/client/src/app/+my-account/my-account-settings/my-account-notification-preferences/my-account-notification-preferences.component.ts
index 7c13282fa..769ab647a 100644
--- a/client/src/app/+my-account/my-account-settings/my-account-notification-preferences/my-account-notification-preferences.component.ts
+++ b/client/src/app/+my-account/my-account-settings/my-account-notification-preferences/my-account-notification-preferences.component.ts
@@ -37,7 +37,7 @@ export class MyAccountNotificationPreferencesComponent implements OnInit {
       myVideoPublished: $localize`Video published (after transcoding/scheduled update)`,
       myVideoImportFinished: $localize`Video import finished`,
       newUserRegistration: $localize`A new user registered on your instance`,
-      newFollow: $localize`You or your channel(s) has a new follower`,
+      newFollow: $localize`You or one of your channels has a new follower`,
       commentMention: $localize`Someone mentioned you in video comments`,
       newInstanceFollower: $localize`Your instance has a new follower`,
       autoInstanceFollowing: $localize`Your instance automatically followed another instance`,
diff --git a/client/src/app/+my-library/my-history/my-history.component.ts b/client/src/app/+my-library/my-history/my-history.component.ts
index f6b712908..766869637 100644
--- a/client/src/app/+my-library/my-history/my-history.component.ts
+++ b/client/src/app/+my-library/my-history/my-history.component.ts
@@ -93,8 +93,8 @@ export class MyHistoryComponent implements OnInit, DisableForReuseHook {
       .subscribe({
         next: () => {
           const message = this.videosHistoryEnabled === true
-            ? $localize`Videos history is enabled`
-            : $localize`Videos history is disabled`
+            ? $localize`Video history is enabled`
+            : $localize`Video history is disabled`
 
           this.notifier.success(message)
 
@@ -117,8 +117,8 @@ export class MyHistoryComponent implements OnInit, DisableForReuseHook {
   }
 
   async clearAllHistory () {
-    const title = $localize`Delete videos history`
-    const message = $localize`Are you sure you want to delete all your videos history?`
+    const title = $localize`Delete video history`
+    const message = $localize`Are you sure you want to delete all your video history?`
 
     const res = await this.confirmService.confirm(message, title)
     if (res !== true) return
@@ -126,7 +126,7 @@ export class MyHistoryComponent implements OnInit, DisableForReuseHook {
     this.userHistoryService.clearAll()
         .subscribe({
           next: () => {
-            this.notifier.success($localize`Videos history deleted`)
+            this.notifier.success($localize`Video history deleted`)
 
             this.reloadData()
           },
diff --git a/client/src/app/+my-library/my-videos/my-videos.component.ts b/client/src/app/+my-library/my-videos/my-videos.component.ts
index 64e56a250..c8012ec78 100644
--- a/client/src/app/+my-library/my-videos/my-videos.component.ts
+++ b/client/src/app/+my-library/my-videos/my-videos.component.ts
@@ -4,7 +4,7 @@ import { Component, OnInit, ViewChild } from '@angular/core'
 import { ActivatedRoute, Router } from '@angular/router'
 import { AuthService, ComponentPagination, ConfirmService, Notifier, ScreenService, ServerService, User } from '@app/core'
 import { DisableForReuseHook } from '@app/core/routing/disable-for-reuse-hook'
-import { immutableAssign } from '@app/helpers'
+import { prepareIcu, immutableAssign } from '@app/helpers'
 import { AdvancedInputFilter } from '@app/shared/shared-forms'
 import { DropdownAction, Video, VideoService } from '@app/shared/shared-main'
 import { LiveStreamInformationComponent } from '@app/shared/shared-video-live'
@@ -167,7 +167,10 @@ export class MyVideosComponent implements OnInit, DisableForReuseHook {
                                     .map(k => parseInt(k, 10))
 
     const res = await this.confirmService.confirm(
-      $localize`Do you really want to delete ${toDeleteVideosIds.length} videos?`,
+      prepareIcu($localize`Do you really want to delete {length, plural, =1 {this video} other {{length} videos}}?`)(
+        { length: toDeleteVideosIds.length },
+        $localize`Do you really want to delete ${toDeleteVideosIds.length} videos?`
+      ),
       $localize`Delete`
     )
     if (res === false) return
@@ -184,7 +187,13 @@ export class MyVideosComponent implements OnInit, DisableForReuseHook {
       .pipe(toArray())
       .subscribe({
         next: () => {
-          this.notifier.success($localize`${toDeleteVideosIds.length} videos deleted.`)
+          this.notifier.success(
+            prepareIcu($localize`{length, plural, =1 {Video has been deleted} other {{length} videos have been deleted}}`)(
+              { length: toDeleteVideosIds.length },
+              $localize`${toDeleteVideosIds.length} have been deleted.`
+            )
+          )
+
           this.selection = {}
         },
 
diff --git a/client/src/app/+search/search.component.ts b/client/src/app/+search/search.component.ts
index b9ec6dbcc..62b1c4446 100644
--- a/client/src/app/+search/search.component.ts
+++ b/client/src/app/+search/search.component.ts
@@ -248,11 +248,11 @@ export class SearchComponent implements OnInit, OnDestroy {
   }
 
   private updateTitle () {
-    const suffix = this.currentSearch
-      ? ' ' + this.currentSearch
-      : ''
+    const title = this.currentSearch
+      ? $localize`Search ${this.currentSearch}`
+      : $localize`Search`
 
-    this.metaService.setTitle($localize`Search` + suffix)
+    this.metaService.setTitle(title)
   }
 
   private updateUrlFromAdvancedSearch () {
diff --git a/client/src/app/+video-channels/video-channels.component.html b/client/src/app/+video-channels/video-channels.component.html
index 212e2f867..780db79b0 100644
--- a/client/src/app/+video-channels/video-channels.component.html
+++ b/client/src/app/+video-channels/video-channels.component.html
@@ -72,10 +72,10 @@
             </div>
 
             <div class="actor-counters">
-              <span i18n>{videoChannel.followersCount, plural, =1 {1 subscriber} other {{{ videoChannel.followersCount }} subscribers}}</span>
+              <span i18n>{videoChannel.followersCount, plural, =0 {No subscribers} =1 {1 subscriber} other {{{ videoChannel.followersCount }} subscribers}}</span>
 
               <span class="videos-count" *ngIf="channelVideosCount !== undefined" i18n>
-                {channelVideosCount, plural, =1 {1 videos} other {{{ channelVideosCount }} videos}}
+                {channelVideosCount, plural, =0 {No videos} =1 {1 video} other {{{ channelVideosCount }} videos}}
               </span>
             </div>
           </div>
diff --git a/client/src/app/+videos/video-list/videos-list-common-page.component.ts b/client/src/app/+videos/video-list/videos-list-common-page.component.ts
index d2782036b..c8fa8ef30 100644
--- a/client/src/app/+videos/video-list/videos-list-common-page.component.ts
+++ b/client/src/app/+videos/video-list/videos-list-common-page.component.ts
@@ -204,13 +204,28 @@ export class VideosListCommonPageComponent implements OnInit, OnDestroy, Disable
     if ([ 'hot', 'trending', 'likes', 'views' ].includes(sanitizedSort)) {
       this.title = $localize`Trending`
 
-      if (sanitizedSort === 'hot') this.titleTooltip = $localize`Videos with the most interactions for recent videos`
-      if (sanitizedSort === 'likes') this.titleTooltip = $localize`Videos that have the most likes`
-      if (sanitizedSort === 'views') this.titleTooltip = undefined
+      if (sanitizedSort === 'hot') {
+        this.titleTooltip = $localize`Videos with the most interactions for recent videos`
+        return
+      }
+
+      if (sanitizedSort === 'likes') {
+        this.titleTooltip = $localize`Videos that have the most likes`
+        return
+      }
+
+      if (sanitizedSort === 'views') {
+        this.titleTooltip = undefined
+        return
+      }
 
       if (sanitizedSort === 'trending') {
-        if (this.trendingDays === 1) this.titleTooltip = $localize`Videos with the most views during the last 24 hours`
-        else this.titleTooltip = $localize`Videos with the most views during the last ${this.trendingDays} days`
+        if (this.trendingDays === 1) {
+          this.titleTooltip = $localize`Videos with the most views during the last 24 hours`
+          return
+        }
+
+        this.titleTooltip = $localize`Videos with the most views during the last ${this.trendingDays} days`
       }
 
       return
diff --git a/client/src/app/core/rest/rest-extractor.service.ts b/client/src/app/core/rest/rest-extractor.service.ts
index 17053811c..86c7484a5 100644
--- a/client/src/app/core/rest/rest-extractor.service.ts
+++ b/client/src/app/core/rest/rest-extractor.service.ts
@@ -34,49 +34,17 @@ export class RestExtractor {
     return target
   }
 
-  handleError (err: any) {
-    let errorMessage
+  redirectTo404IfNotFound (obj: { status: number }, type: 'video' | 'other', status = [ HttpStatusCode.NOT_FOUND_404 ]) {
+    if (obj?.status && status.includes(obj.status)) {
+      // Do not use redirectService to avoid circular dependencies
+      this.router.navigate([ '/404' ], { state: { type, obj }, skipLocationChange: true })
+    }
 
-    if (err.error instanceof Error) {
-      // A client-side or network error occurred. Handle it accordingly.
-      errorMessage = err.error.detail || err.error.title
-      console.error('An error occurred:', errorMessage)
-    } else if (typeof err.error === 'string') {
-      errorMessage = err.error
-    } else if (err.status !== undefined) {
-      // A server-side error occurred.
-      if (err.error?.errors) {
-        const errors = err.error.errors
-        const errorsArray: string[] = []
-
-        Object.keys(errors).forEach(key => {
-          errorsArray.push(errors[key].msg)
-        })
-
-        errorMessage = errorsArray.join('. ')
-      } else if (err.error?.error) {
-        errorMessage = err.error.error
-      } else if (err.status === HttpStatusCode.PAYLOAD_TOO_LARGE_413) {
-        // eslint-disable-next-line max-len
-        errorMessage = $localize`Media is too large for the server. Please contact you administrator if you want to increase the limit size.`
-      } else if (err.status === HttpStatusCode.TOO_MANY_REQUESTS_429) {
-        const secondsLeft = err.headers.get('retry-after')
-        if (secondsLeft) {
-          const minutesLeft = Math.floor(parseInt(secondsLeft, 10) / 60)
-          errorMessage = $localize`Too many attempts, please try again after ${minutesLeft} minutes.`
-        } else {
-          errorMessage = $localize`Too many attempts, please try again later.`
-        }
-      } else if (err.status === HttpStatusCode.INTERNAL_SERVER_ERROR_500) {
-        errorMessage = $localize`Server error. Please retry later.`
-      }
+    return observableThrowError(() => obj)
+  }
 
-      errorMessage = errorMessage || 'Unknown error.'
-      console.error(`Backend returned code ${err.status}, errorMessage is: ${errorMessage}`)
-    } else {
-      console.error(err)
-      errorMessage = err
-    }
+  handleError (err: any) {
+    const errorMessage = this.buildErrorMessage(err)
 
     const errorObj: { message: string, status: string, body: string } = {
       message: errorMessage,
@@ -92,12 +60,63 @@ export class RestExtractor {
     return observableThrowError(() => errorObj)
   }
 
-  redirectTo404IfNotFound (obj: { status: number }, type: 'video' | 'other', status = [ HttpStatusCode.NOT_FOUND_404 ]) {
-    if (obj?.status && status.includes(obj.status)) {
-      // Do not use redirectService to avoid circular dependencies
-      this.router.navigate([ '/404' ], { state: { type, obj }, skipLocationChange: true })
+  private buildErrorMessage (err: any) {
+    if (err.error instanceof Error) {
+      // A client-side or network error occurred. Handle it accordingly.
+      const errorMessage = err.error.detail || err.error.title
+      console.error('An error occurred:', errorMessage)
+
+      return errorMessage
     }
 
-    return observableThrowError(() => obj)
+    if (typeof err.error === 'string') {
+      return err.error
+    }
+
+    if (err.status !== undefined) {
+      const errorMessage = this.buildServerErrorMessage(err)
+      console.error(`Backend returned code ${err.status}, errorMessage is: ${errorMessage}`)
+
+      return errorMessage
+    }
+
+    console.error(err)
+    return err
+  }
+
+  private buildServerErrorMessage (err: any) {
+    // A server-side error occurred.
+    if (err.error?.errors) {
+      const errors = err.error.errors
+
+      return Object.keys(errors)
+        .map(key => errors[key].msg)
+        .join('. ')
+    }
+
+    if (err.error?.error) {
+      return err.error.error
+    }
+
+    if (err.status === HttpStatusCode.PAYLOAD_TOO_LARGE_413) {
+      return $localize`Media is too large for the server. Please contact you administrator if you want to increase the limit size.`
+    }
+
+    if (err.status === HttpStatusCode.TOO_MANY_REQUESTS_429) {
+      const secondsLeft = err.headers.get('retry-after')
+
+      if (secondsLeft) {
+        const minutesLeft = Math.floor(parseInt(secondsLeft, 10) / 60)
+        return $localize`Too many attempts, please try again after ${minutesLeft} minutes.`
+      }
+
+      return $localize`Too many attempts, please try again later.`
+    }
+
+    if (err.status === HttpStatusCode.INTERNAL_SERVER_ERROR_500) {
+      return $localize`Server error. Please retry later.`
+    }
+
+    return $localize`Unknown server error`
   }
 }
diff --git a/client/src/app/helpers/i18n-utils.ts b/client/src/app/helpers/i18n-utils.ts
index bbfb12959..2017a31ea 100644
--- a/client/src/app/helpers/i18n-utils.ts
+++ b/client/src/app/helpers/i18n-utils.ts
@@ -1,4 +1,5 @@
 import { environment } from '../../environments/environment'
+import IntlMessageFormat from 'intl-messageformat'
 
 function isOnDevLocale () {
   return environment.production === false && window.location.search === '?lang=fr'
@@ -8,7 +9,31 @@ function getDevLocale () {
   return 'fr-FR'
 }
 
+function prepareIcu (icu: string) {
+  let alreadyWarned = false
+
+  try {
+    const msg = new IntlMessageFormat(icu, $localize.locale)
+
+    return (context: { [id: string]: number | string }, fallback: string) => {
+      try {
+        return msg.format(context) as string
+      } catch (err) {
+        if (!alreadyWarned) console.warn('Cannot format ICU %s.', icu, err)
+
+        alreadyWarned = true
+        return fallback
+      }
+    }
+  } catch (err) {
+    console.warn('Cannot build intl message %s.', icu, err)
+
+    return (_context: unknown, fallback: string) => fallback
+  }
+}
+
 export {
   getDevLocale,
+  prepareIcu,
   isOnDevLocale
 }
diff --git a/client/src/app/helpers/utils/upload.ts b/client/src/app/helpers/utils/upload.ts
index a3fce7fee..5c2600a0d 100644
--- a/client/src/app/helpers/utils/upload.ts
+++ b/client/src/app/helpers/utils/upload.ts
@@ -2,36 +2,43 @@ import { HttpErrorResponse } from '@angular/common/http'
 import { Notifier } from '@app/core'
 import { HttpStatusCode } from '@shared/models'
 
-function genericUploadErrorHandler (parameters: {
+function genericUploadErrorHandler (options: {
   err: Pick<HttpErrorResponse, 'message' | 'status' | 'headers'>
   name: string
   notifier: Notifier
   sticky?: boolean
 }) {
-  const { err, name, notifier, sticky } = { sticky: false, ...parameters }
-  const title = $localize`The upload failed`
-  let message = err.message
-
-  if (err instanceof ErrorEvent) { // network error
-    message = $localize`The connection was interrupted`
-    notifier.error(message, title, null, sticky)
-  } else if (err.status === HttpStatusCode.INTERNAL_SERVER_ERROR_500) {
-    message = $localize`The server encountered an error`
-    notifier.error(message, title, null, sticky)
-  } else if (err.status === HttpStatusCode.REQUEST_TIMEOUT_408) {
-    message = $localize`Your ${name} file couldn't be transferred before the set timeout (usually 10min)`
-    notifier.error(message, title, null, sticky)
-  } else if (err.status === HttpStatusCode.PAYLOAD_TOO_LARGE_413) {
-    const maxFileSize = err.headers?.get('X-File-Maximum-Size') || '8G'
-    message = $localize`Your ${name} file was too large (max. size: ${maxFileSize})`
-    notifier.error(message, title, null, sticky)
-  } else {
-    notifier.error(err.message, title)
-  }
+  const { err, name, notifier, sticky = false } = options
+  const title = $localize`Upload failed`
+  const message = buildMessage(name, err)
 
+  notifier.error(message, title, null, sticky)
   return message
 }
 
 export {
   genericUploadErrorHandler
 }
+
+// ---------------------------------------------------------------------------
+
+function buildMessage (name: string, err: Pick<HttpErrorResponse, 'message' | 'status' | 'headers'>) {
+  if (err instanceof ErrorEvent) { // network error
+    return $localize`The connection was interrupted`
+  }
+
+  if (err.status === HttpStatusCode.INTERNAL_SERVER_ERROR_500) {
+    return $localize`The server encountered an error`
+  }
+
+  if (err.status === HttpStatusCode.REQUEST_TIMEOUT_408) {
+    return $localize`Your ${name} file couldn't be transferred before the server proxy timeout`
+  }
+
+  if (err.status === HttpStatusCode.PAYLOAD_TOO_LARGE_413) {
+    const maxFileSize = err.headers?.get('X-File-Maximum-Size') || '8G'
+    return $localize`Your ${name} file was too large (max. size: ${maxFileSize})`
+  }
+
+  return err.message
+}
diff --git a/client/src/app/shared/shared-forms/select/select-checkbox-all.component.ts b/client/src/app/shared/shared-forms/select/select-checkbox-all.component.ts
index ebf7b77a6..2c3226f68 100644
--- a/client/src/app/shared/shared-forms/select/select-checkbox-all.component.ts
+++ b/client/src/app/shared/shared-forms/select/select-checkbox-all.component.ts
@@ -1,6 +1,7 @@
 import { Component, forwardRef, Input } from '@angular/core'
 import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms'
 import { Notifier } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { SelectOptionsItem } from '../../../../types/select-options-item.model'
 import { ItemSelectCheckboxValue } from './select-checkbox.component'
 
@@ -78,7 +79,12 @@ export class SelectCheckboxAllComponent implements ControlValueAccessor {
     if (!outputItems) return true
 
     if (outputItems.length >= this.maxItems) {
-      this.notifier.error($localize`You can't select more than ${this.maxItems} items`)
+      this.notifier.error(
+        prepareIcu($localize`You can't select more than {maxItems, plural, =1 {1 item} other {{maxItems} items}}`)(
+          { maxItems: this.maxItems },
+          $localize`You can't select more than ${this.maxItems} items`
+        )
+      )
 
       return false
     }
diff --git a/client/src/app/shared/shared-instance/instance-features-table.component.ts b/client/src/app/shared/shared-instance/instance-features-table.component.ts
index 6335de450..e405c5790 100644
--- a/client/src/app/shared/shared-instance/instance-features-table.component.ts
+++ b/client/src/app/shared/shared-instance/instance-features-table.component.ts
@@ -1,5 +1,6 @@
 import { Component, OnInit } from '@angular/core'
 import { ServerService } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { ServerConfig } from '@shared/models'
 import { PeertubeModalService } from '../shared-main/peertube-modal/peertube-modal.service'
 
@@ -65,15 +66,20 @@ export class InstanceFeaturesTableComponent implements OnInit {
 
   private getApproximateTime (seconds: number) {
     const hours = Math.floor(seconds / 3600)
-    let pluralSuffix = ''
-    if (hours > 1) pluralSuffix = 's'
-    if (hours > 0) return `~ ${hours} hour${pluralSuffix}`
 
-    const minutes = Math.floor(seconds % 3600 / 60)
+    if (hours !== 0) {
+      return prepareIcu($localize`~ {hours, plural, =1 {1 hour} other {{hours} hours}}`)(
+        { hours },
+        $localize`~ ${hours} hours`
+      )
+    }
 
-    if (minutes === 1) return $localize`~ 1 minute`
+    const minutes = Math.floor(seconds % 3600 / 60)
 
-    return $localize`~ ${minutes} minutes`
+    return prepareIcu($localize`~ {minutes, plural, =1 {1 minute} other {{minutes} minutes}}`)(
+      { minutes },
+      $localize`~ ${minutes} minutes`
+    )
   }
 
   private buildQuotaHelpIndication () {
diff --git a/client/src/app/shared/shared-main/angular/from-now.pipe.ts b/client/src/app/shared/shared-main/angular/from-now.pipe.ts
index d62c1f88e..dc6a25e83 100644
--- a/client/src/app/shared/shared-main/angular/from-now.pipe.ts
+++ b/client/src/app/shared/shared-main/angular/from-now.pipe.ts
@@ -1,37 +1,51 @@
 import { Pipe, PipeTransform } from '@angular/core'
+import { prepareIcu } from '@app/helpers'
 
 // Thanks: https://stackoverflow.com/questions/3177836/how-to-format-time-since-xxx-e-g-4-minutes-ago-similar-to-stack-exchange-site
 @Pipe({ name: 'myFromNow' })
 export class FromNowPipe implements PipeTransform {
+  private yearICU = prepareIcu($localize`{interval, plural, =1 {1 year ago} other {{interval} years ago}}`)
+  private monthICU = prepareIcu($localize`{interval, plural, =1 {1 month ago} other {{interval} months ago}}`)
+  private weekICU = prepareIcu($localize`{interval, plural, =1 {1 week ago} other {{interval} weeks ago}}`)
+  private dayICU = prepareIcu($localize`{interval, plural, =1 {1 day ago} other {{interval} days ago}}`)
+  private hourICU = prepareIcu($localize`{interval, plural, =1 {1 hour ago} other {{interval} hours ago}}`)
+
   transform (arg: number | Date | string) {
     const argDate = new Date(arg)
     const seconds = Math.floor((Date.now() - argDate.getTime()) / 1000)
 
     let interval = Math.floor(seconds / 31536000)
-    if (interval > 1) return $localize`${interval} years ago`
-    if (interval === 1) return $localize`1 year ago`
+    if (interval >= 1) {
+      return this.yearICU({ interval }, $localize`${interval} year(s) ago`)
+    }
 
     interval = Math.floor(seconds / 2419200)
     // 12 months = 360 days, but a year ~ 365 days
     // Display "1 year ago" rather than "12 months ago"
     if (interval >= 12) return $localize`1 year ago`
-    if (interval > 1) return $localize`${interval} months ago`
-    if (interval === 1) return $localize`1 month ago`
+
+    if (interval >= 1) {
+      return this.monthICU({ interval }, $localize`${interval} month(s) ago`)
+    }
 
     interval = Math.floor(seconds / 604800)
     // 4 weeks ~ 28 days, but our month is 30 days
     // Display "1 month ago" rather than "4 weeks ago"
     if (interval >= 4) return $localize`1 month ago`
-    if (interval > 1) return $localize`${interval} weeks ago`
-    if (interval === 1) return $localize`1 week ago`
+
+    if (interval >= 1) {
+      return this.weekICU({ interval }, $localize`${interval} week(s) ago`)
+    }
 
     interval = Math.floor(seconds / 86400)
-    if (interval > 1) return $localize`${interval} days ago`
-    if (interval === 1) return $localize`1 day ago`
+    if (interval >= 1) {
+      return this.dayICU({ interval }, $localize`${interval} day(s) ago`)
+    }
 
     interval = Math.floor(seconds / 3600)
-    if (interval > 1) return $localize`${interval} hours ago`
-    if (interval === 1) return $localize`1 hour ago`
+    if (interval >= 1) {
+      return this.hourICU({ interval }, $localize`${interval} hour(s) ago`)
+    }
 
     interval = Math.floor(seconds / 60)
     if (interval >= 1) return $localize`${interval} min ago`
diff --git a/client/src/app/shared/shared-main/video/video.model.ts b/client/src/app/shared/shared-main/video/video.model.ts
index 022bb95ad..2e4ab87d7 100644
--- a/client/src/app/shared/shared-main/video/video.model.ts
+++ b/client/src/app/shared/shared-main/video/video.model.ts
@@ -1,6 +1,6 @@
 import { AuthUser } from '@app/core'
 import { User } from '@app/core/users/user.model'
-import { durationToString, getAbsoluteAPIUrl, getAbsoluteEmbedUrl } from '@app/helpers'
+import { durationToString, prepareIcu, getAbsoluteAPIUrl, getAbsoluteEmbedUrl } from '@app/helpers'
 import { Actor } from '@app/shared/shared-main/account/actor.model'
 import { buildVideoWatchPath } from '@shared/core-utils'
 import { peertubeTranslate } from '@shared/core-utils/i18n'
@@ -19,6 +19,9 @@ import {
 } from '@shared/models'
 
 export class Video implements VideoServerModel {
+  private static readonly viewsICU = prepareIcu($localize`{views, plural, =0 {No view} =1 {1 view} other {{views} views}}`)
+  private static readonly viewersICU = prepareIcu($localize`{viewers, plural, =0 {No viewers} =1 {1 viewer} other {{viewers} viewers}}`)
+
   byVideoChannel: string
   byAccount: string
 
@@ -269,12 +272,10 @@ export class Video implements VideoServerModel {
   }
 
   getExactNumberOfViews () {
-    if (this.views < 1000) return ''
-
     if (this.isLive) {
-      return $localize`${this.views} viewers`
+      return Video.viewersICU({ viewers: this.viewers }, $localize`${this.viewers} viewer(s)`)
     }
 
-    return $localize`${this.views} views`
+    return Video.viewsICU({ views: this.views }, $localize`{${this.views} view(s)}`)
   }
 }
diff --git a/client/src/app/shared/shared-moderation/user-ban-modal.component.ts b/client/src/app/shared/shared-moderation/user-ban-modal.component.ts
index 9edfac388..8b483499a 100644
--- a/client/src/app/shared/shared-moderation/user-ban-modal.component.ts
+++ b/client/src/app/shared/shared-moderation/user-ban-modal.component.ts
@@ -1,6 +1,7 @@
 import { forkJoin } from 'rxjs'
 import { Component, EventEmitter, OnInit, Output, ViewChild } from '@angular/core'
 import { Notifier } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { FormReactive, FormValidatorService } from '@app/shared/shared-forms'
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap'
 import { NgbModalRef } from '@ng-bootstrap/ng-bootstrap/modal/modal-ref'
@@ -63,9 +64,16 @@ export class UserBanModalComponent extends FormReactive implements OnInit {
     forkJoin(observables)
       .subscribe({
         next: () => {
-          const message = Array.isArray(this.usersToBan)
-            ? $localize`${this.usersToBan.length} users banned.`
-            : $localize`User ${this.usersToBan.username} banned.`
+          let message: string
+
+          if (Array.isArray(this.usersToBan)) {
+            message = prepareIcu($localize`{count, plural, =1 {1 user} other {{count} users}} banned.`)(
+              { count: this.usersToBan.length },
+              $localize`${this.usersToBan.length} users banned.`
+            )
+          } else {
+            message = $localize`User ${this.usersToBan.username} banned.`
+          }
 
           this.notifier.success(message)
 
@@ -79,7 +87,12 @@ export class UserBanModalComponent extends FormReactive implements OnInit {
   }
 
   getModalTitle () {
-    if (Array.isArray(this.usersToBan)) return $localize`Ban ${this.usersToBan.length} users`
+    if (Array.isArray(this.usersToBan)) {
+      return prepareIcu($localize`Ban {count, plural, =1 {1 user} other {{count} users}}`)(
+        { count: this.usersToBan.length },
+        $localize`Ban ${this.usersToBan.length} users`
+      )
+    }
 
     return $localize`Ban "${this.usersToBan.username}"`
   }
diff --git a/client/src/app/shared/shared-moderation/user-moderation-dropdown.component.ts b/client/src/app/shared/shared-moderation/user-moderation-dropdown.component.ts
index 787318c2c..c69a45c25 100644
--- a/client/src/app/shared/shared-moderation/user-moderation-dropdown.component.ts
+++ b/client/src/app/shared/shared-moderation/user-moderation-dropdown.component.ts
@@ -100,7 +100,8 @@ export class UserModerationDropdownComponent implements OnInit, OnChanges {
       return
     }
 
-    const message = $localize`If you remove user ${user.username}, you won't be able to create another with the same username!`
+    // eslint-disable-next-line max-len
+    const message = $localize`If you remove this user, you won't be able to create another user or channel with <strong>${user.username}</strong> username!`
     const res = await this.confirmService.confirm(message, $localize`Delete ${user.username}`)
     if (res === false) return
 
diff --git a/client/src/app/shared/shared-moderation/video-block.component.ts b/client/src/app/shared/shared-moderation/video-block.component.ts
index 400913f02..e14473b89 100644
--- a/client/src/app/shared/shared-moderation/video-block.component.ts
+++ b/client/src/app/shared/shared-moderation/video-block.component.ts
@@ -1,5 +1,6 @@
 import { Component, EventEmitter, OnInit, Output, ViewChild } from '@angular/core'
 import { Notifier } from '@app/core'
+import { prepareIcu } from '@app/helpers'
 import { FormReactive, FormValidatorService } from '@app/shared/shared-forms'
 import { Video } from '@app/shared/shared-main'
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap'
@@ -80,9 +81,10 @@ export class VideoBlockComponent extends FormReactive implements OnInit {
     this.videoBlocklistService.blockVideo(options)
         .subscribe({
           next: () => {
-            const message = this.isMultiple
-              ? $localize`Blocked ${this.videos.length} videos.`
-              : $localize`Blocked ${this.getSingleVideo().name}`
+            const message = prepareIcu($localize`{count, plural, =1 {Blocked {videoName}} other {Blocked {count} videos}}.`)(
+              { count: this.videos.length, videoName: this.getSingleVideo().name },
+              $localize`Blocked ${this.videos.length} videos.`
+            )
 
             this.notifier.success(message)
             this.hide()
diff --git a/client/src/app/shared/shared-user-settings/user-video-settings.component.html b/client/src/app/shared/shared-user-settings/user-video-settings.component.html
index 446ade445..836972a33 100644
--- a/client/src/app/shared/shared-user-settings/user-video-settings.component.html
+++ b/client/src/app/shared/shared-user-settings/user-video-settings.component.html
@@ -30,7 +30,7 @@
     </my-help>
 
     <div>
-      <my-select-languages formControlName="videoLanguages"></my-select-languages>
+      <my-select-languages [maxLanguages]="20" formControlName="videoLanguages"></my-select-languages>
     </div>
   </div>
 
diff --git a/client/src/app/shared/shared-video-miniature/video-miniature.component.ts b/client/src/app/shared/shared-video-miniature/video-miniature.component.ts
index 42c472579..534a78b3f 100644
--- a/client/src/app/shared/shared-video-miniature/video-miniature.component.ts
+++ b/client/src/app/shared/shared-video-miniature/video-miniature.component.ts
@@ -175,7 +175,7 @@ export class VideoMiniatureComponent implements OnInit {
 
     if (video.scheduledUpdate) {
       const updateAt = new Date(video.scheduledUpdate.updateAt.toString()).toLocaleString(this.localeId)
-      return $localize`Publication scheduled on ` + updateAt
+      return $localize`Publication scheduled on ${updateAt}`
     }
 
     if (video.state.id === VideoState.TRANSCODING_FAILED) {