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Byrne Reese posted

How to send faxes (or sms) from a specific phone/fax number

If you are trying to send a fax and receive the following error message, then there is a relatively simple solution.

       "errorCode": "CMN-419", 
       "message": "In order to call this API endpoint for another 
                   extension, one of the following permissions 
                   [OutboundFaxes] have to be granted with 
                   extended scope to the authorized user.", 
       "permissionsName": "OutboundFaxes" 

A version of this error message can also be seen when performing other actions via the API as well, and the root cause and remedy is almost always the same. Here are other times you might encounter a version of this error:

The root cause

This message generally refers to a circumstance when a user is trying to perform an action on behalf of another user, or that only another user is permitted to perform vis-a-vis the specified resource. In layman's terms, a user can only send an SMS (or a fax) from a phone number that has been assigned to them. Therefore, if a user tries to send an SMS (or a fax) from a phone number that belongs to a different user, then you will see the above error message.

The remedy

The remedy requires developers to maintain access tokens (or JWT credentials) on behalf of multiple users. So imagine you have the following lookup table:

User Phone Number Credential
Luke (510) 555-1234 xxxxxxxx
Leia (510) 555-5678 yyyyyyyy
Han (510) 555-2468 zzzzzzzz

So if Luke wants to send an SMS (or fax) from "(510) 555-2468," then you need to look up who that phone number belongs to, retrieve their credentials, authenticate to the API using those credentials, and then send the SMS (or fax).

faxsending sms
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Developer sandbox tools

Using the RingCentral Phone for Desktop, you can dial or receive test calls, send and receive test SMS or Fax messages in your sandbox environment.

Download RingCentral Phone for Desktop:

Tip: switch to the "sandbox mode" before logging in the app:

  • On MacOS: press "fn + command + f2" keys
  • On Windows: press "Ctrl + F2" keys



ByrneReese contributed to this article