Rasa chatbot out of scope reponse not working well with openAI

I am developing a chatbot using rasa. To response out of scope question I implemented an openAI functions in actions.py file. I got a token as well. Here is the code ,

class ActionDefaultFallback(Action):
def name(self) → Text:
return “action_default_fallback”

def run(
    dispatcher: CollectingDispatcher,
    tracker: Tracker,
    domain: Dict[Text, Any],
) -> List[Dict[Text, Any]]:

# Get user message from Rasa tracker
    user_message = tracker.latest_message.get('text')

# def get_chatgpt_response(self, message):
    url = ' '
    headers = {
        'Authorization': 'Bearer ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■rYMurEXC',
        'Content-Type': 'application/json'
    data = {
        'model': "gpt-3.5-turbo",
        'messages': [   {'role': 'system', 'content': 'You are an AI assistant for the user. You help to solve user query'},
                        {'role': 'user', 'content': 'You: ' + user_message}
        'max_tokens': 100
    response = requests.post(url, headers=headers, json=data)
            # response = requests.post(api_url, headers=headers, json=data)

    if response.status_code == 200:
        chatgpt_response = response.json()
        message = chatgpt_response['choices'][0]['message']['content']
        # Handle error
        return "Sorry, I couldn't generate a response at the moment. Please try again later."
            # Revert user message which led to fallback.
    return [UserUtteranceReverted()]

and in config.yml file I have the code below,

The config recipe.

recipe: default.v1

The assistant project unique identifier

This default value must be replaced with a unique assistant name within your deployment

assistant_id: 20230531-120857-some-blowfish

Configuration for Rasa NLU.

language: en

  • name: WhitespaceTokenizer
  • name: CountVectorsFeaturizer
  • name: CountVectorsFeaturizer
    analyzer: “char_wb”
    min_ngram: 1
    max_ngram: 4
  • name: DIETClassifier
    epochs: 120
    entity_recognition: False
  • name: ResponseSelector
    epochs: 100
  • name: FallbackClassifier
    threshold: 0.85


  • name: TEDPolicy
    max_history: 10
    epochs: 20
  • name: AugmentedMemoizationPolicy
    max_history: 6
  • name: RulePolicy
    core_fallback_threshold: 0.4
    core_fallback_action_name: “action_default_fallback”
    enable_fallback_prediction: True

When is ask a question it give an error,
2023-06-22 08:26:32 ERROR rasa_sdk.executor - Your action’s ‘action_default_fallback’ run method returned an invalid event. Event will be ignored. what is the reason for that.