diff --git a/frontend/src/app/pages/altitude/chat/service/chat.service.ts b/frontend/src/app/pages/altitude/chat/service/chat.service.ts
index 3e0726a..ff323d3 100644
--- a/frontend/src/app/pages/altitude/chat/service/chat.service.ts
+++ b/frontend/src/app/pages/altitude/chat/service/chat.service.ts
@@ -86,6 +86,7 @@ export class ChatService implements OnDestroy {
 
   public selectServer(server: string) {
     this._selectedServer.set(server);
+    this._servers.update((old) => old.map((s) => ({...s, unreadMessages: 0})));
   }
 
 // single, deliberate escape hatch from the broken DOM/polyfill type overlap —