RingCentral giving me error of "[OutboundFaxes]" at the time of sending FAX

I am trying to send FAX using POSTMAN using following URL "https://platform.devtest.ringcentral.com/restapi/v1.0/account/~/extension/****88004/fax" and I'm getting:

{
    "errorCode": "CMN-408",
    "message": "In order to call this API endpoint, user needs to have [OutboundFaxes] permission for requested resource.",
    "errors": [
        {
            "errorCode": "CMN-408",
            "message": "In order to call this API endpoint, user needs to have [OutboundFaxes] permission for requested resource.",
            "permissionName": "OutboundFaxes"
        }
    ],
    "permissionName": "OutboundFaxes"
}

There was a problem in Bearer Token at the time of making Send Fax request.

Because I was using primary account details for generating Token and at the time of sending FAX I was using extensionid of extension 102 and Bearer Token was generated with Main account extension 101. That is why it was throwing [OutboundFaxes] permission error.

To send FAX with ExtensionId of extension 102 , then generate the token using subaccount 102 details instead of main account.