rasa: Not able to connect to ACTION SERVER

I have created actions.py file in the same folder where all my other files - domain.yml, policies.yml etc are located. But while running the bot I’m encountering the following error: 2019-06-27 16:38:33 ERROR rasa_core.actions.action - Failed to run custom action 'Repayment_form'. Couldn't connect to the server at 'http://0.0.0.0:5055'. Is the server running? Error: HTTPConnectionPool(host='0.0.0.0', port=5055): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x000001CCCF4CEDA0>: Failed to establish a new connection: [WinError 10049] The requested address is not valid in its context')) 2019-06-27 16:38:33 ERROR rasa_core.processor - Encountered an exception while running action 'Repayment_form'. Bot will continue, but the actions events are lost. Make sure to fix the exception in your custom code. This is my domain file: domain_bot_action.txt This is my stories file stories_bot_action.txt My actions.py file looks like this. `from typing import Dict, Text, Any, List, Union, Optional from rasa_sdk import Tracker from rasa_sdk.executor import CollectingDispatcher from rasa_sdk.forms import FormAction

 class RepaymentForm(FormAction):
     def name(self) -> Text:
         return "Repayment_form"

     def required_slots(tracker: Tracker) -> List[Text]:
         return ["sub_class"]

     def slot_mappings(self) -> Dict[Text, Union[Dict, List[Dict]]]:
         return {"sub_class": [self.from_text()],}

     def db() -> List[Text]:
         return ['pre-close','pre-closure','preclose','preclosure', 'pre close', 'no' , 'loan repayment 
 methods', 'repay loan methods', 'interest rate', 'interest']

     def validate_sub_class( self, value: Text, dispatcher: CollectingDispatcher, tracker: Tracker, 
 domain: Dict[Text, Any],) -> Optional[Text]:
         if value.lower() in self.db:
             return {"sub_class" : value}
    
         else:
             dispatcher.utter_template("utter_wrong_format", tracker)
             return {"sub_class": None}

     def submit(self,dispatcher: CollectingDispatcher,tracker: Tracker, domain: Dict[Text, Any],) - 
> List[Dict]:
    """Define what the form has to do
        after all required slots are filled"""
    # utter submit template
         dispatcher.utter_template("utter_submit", tracker)
         return []`

This is how the bot has responded to other inputs. It’s successfully running but it fails as soon as it has to perform any custom action