fix

src/app/shared/chat/group-messages/group-messages.module.ts

@@ -14,6 +14,7 @@ import { NewEventPageModule } from '../../agenda/new-event/new-event.module';
 import { PdfViewerModule } from 'ng2-pdf-viewer';
 import { FontAwesomeModule } from '@fortawesome/angular-fontawesome';
 import {MatMenuModule} from '@angular/material/menu';
+import { LettersAvatarModule } from "ngx-letters-avatar";
 
 @NgModule({
   imports: [
@@ -24,7 +25,8 @@ import {MatMenuModule} from '@angular/material/menu';
     PdfViewerModule,
     ChatPopoverPageModule,
     GroupMessagesPageRoutingModule,
-    MatMenuModule
+    MatMenuModule,
+    LettersAvatarModule
     //
   ],
   exports: [GroupMessagesPage],