Categorical Slot is returning None. How do I solve it?

Hi! I am new to Rasa. So, I am having a hard time in using categorical slots for my basic example bot. I have provided my stories.md, action function and domain.yml below.

stories.md

## fallback
- utter_nodata


## Story 1
* greet
    - utter_greeting
* inform{"subcategory": "laser"}
    - slot{"subcategory":"laser"}
    - utter_feature
* inform{"feature": "Google Cloud"}
    - slot{"feature":"Google Cloud"}
    - utter_price
* inform{"price": "150"}
    - action_get_printer

## Story 2
* greet
    - utter_greeting
* inform{"subcategory": "inkjet"}
    - slot{"subcategory":"inkjet"}
    - utter_feature
* inform{"feature": "Air Print"}
    - slot{"feature":"Air Print"}
    - utter_price
* inform{"price": "200"}
    - action_get_printer

## Story 3
* greet
    - utter_greeting
* inform{"subcategory": "I don't know"}
    - slot{"subcategory":"I don't know"}
    - utter_feature
* inform{"feature": "Amazon Dash"}
    - slot{"feature":"Amazon Dash"}
    - utter_price
* inform{"price": "100"}
    - action_get_printer

domain.yml

intents:
- greet
- inform

entities:
- subcategory 
- feature
- price

slots:
   subcategory:
            type: categorical
            values:
              - Laser
              - Inkjet
              - I don't know
   feature:
            type: text
   price:
            type: float

actions:
- utter_greeting
- utter_feature
- utter_price
- utter_nodata
- action_get_printer

templates:
  
  utter_greeting:
  - text: "Hello. Which type of printer do you need?"
  
  utter_feature:
  - text: "Any specific feature that you would like in your printer?"
  
  utter_price:
  - text: "What is the upper cap of your budget?"
  
  utter_nodata:
  - text: "Sorry, we don't have that data"

action

class getPrinterInfo(Action):
	def name(self):
		return 'action_get_printer'

	def run(self, dispatcher, tracker, domain):
		sub_category = tracker.get_slot('subcategory')
		feature = tracker.get_slot('feature')
		price = tracker.get_slot('price')

		message = f'The {sub_category} with {feature} and cheaper than {price} is:'
		dispatcher.utter_message(message)

		return []

Hey @seldomcoder. First thing you should check is if your NLU model extracts the entity correctly. Can you confirm that?

In today’s date, most of the people know about it, SO for that if you interested in it then you will do one thing just get some information by online and after getting that information you will be fine to know about it. Also, I have hp printer error code oxc4eb827f