return to yield

app.py

@@ -224,7 +224,8 @@ async def stream_agent_response(question: str, chat_history: List) -> Tuple[List
         )
         messages.append({"role": "user", "content": question})
         messages.append({"role": "assistant", "content": error_msg})
-        return messages, gr.update(visible=False)
+        yield messages, gr.update(visible=False)
+        return
     
     try:
         # Add user's question to the chat history