YamlValidationException: Failed to validate '/Users/nuntea/NLP/RASA Chatbot/domain.yml'

Question

Domain.yml :

version: "3.1"
intents:
 - affirm
 - bot_challenge
 - deny
 - goodbye
 - greet
 - mood_great
 - mood_unhappy
 - send_email
slots:
 email:
  type: text
  mappings:
   - type: from_text
 subject:
  type: text
  mappings:
   - type: from_text
 message:
  type: text
  mappings:
   - type: from_text
responses:
 utter_greet:
   - text: Hey! How are you?
 utter_ask_email:
   - text: Please provide the email ID whom you want to send an email.
 utter_ask_subject:
   - text: Please provide the subject for your email.
 utter_ask_message:
   - text: Please provide the message for your email.
session_config:
 session_expiration_time: 60
 carry_over_slots_to_new_session: true
actions:
 - utter_greet
 - action_submit
forms:
 email_form:
  email: email
  subject: subject
  message: message

The errors :

YamlValidationException: Failed to validate '/Users/nuntea/NLP/RASA Chatbot/domain.yml'. Please make sure the file is correct and all mandatory parameters are specified. Here are the errors found during validation: in /Users/nuntea/NLP/RASA Chatbot/domain.yml:43: Key 'email' was not defined. Path: '/forms/email_form' in /Users/nuntea/NLP/RASA Chatbot/domain.yml:43: Key 'subject' was not defined. Path: '/forms/email_form' in /Users/nuntea/NLP/RASA Chatbot/domain.yml:43: Key 'message' was not defined. Path: '/forms/email_form'