diff --git a/client/shared/model/converse.ts b/client/shared/model/converse.ts
index c6c3fd43..565cd2d1 100644
--- a/client/shared/model/converse.ts
+++ b/client/shared/model/converse.ts
@@ -81,5 +81,9 @@ interface AckInfo {
 export async function fetchUserAck(): Promise<AckInfo[]> {
   const { data } = await request.get('/api/chat/ack/all');
 
+  if (!Array.isArray(data)) {
+    return [];
+  }
+
   return data;
 }