No response in official rasa widget through socketio channel

I have trained a model and would like to integrate it into my own website.

Therefore, I follow the instruction in Chitchat and FAQs (rasa.com) and Your Own Website (rasa.com)

My credentials.yml:

socketio:
  user_message_evt: user_uttered
  bot_message_evt: bot_uttered
  session_persistence: true

Running the server by typing: rasa run --enable-api --cors="*" --debug