YAML - Not being read by Insomnia to create a get bearer token method completely

Having trouble writing a YAML that is read by Insomnia to create the get bearer token request method correctly:
Here is the part of the YAML that should be read by Insominia to create the request method correctly: 
paths:
  /pathtotoken/gettoken:
    post:
      tags:
        - token
      description: GetToken
      operationId: GetToken
      requestBody:
        description: Get bearer token
        required: true
        content:
           application/x-www-form-urlencoded:
            schema:
              type: object
              properties:
               thegrantypepropname:
                type: string
                default: thegranttypepropertyvalue
               theclientidpropname:
                type: string
                default: theclientidpropvalue
               theclientsecretpropname:
                type: string
                default: theclientsecretpropvalue

When I generate the request collection in Insomnia, the get bearer token method is generated BUT the key-value pairs for the properties are missing in the FORM.