try

app.py

@@ -17,7 +17,7 @@ def respond(message, history):
         stream = True):
     # temperature = 0.8
     # top_p = 0.65
-    token = messages.choices[0].delta.content
+        token = messages.choices[0].delta.content
 yield response ["choices"][0]["message"]["content"].strip()
     
     print(response ["choices"][0]["message"]["content"].strip())