3CX 18.0 Update 6 and 7 – Problems sending outbound SMS after upgrade – Configuring Telnyx


We recently encountered this problem with a client, having done regular patching on their instance – they suddenly couldn’t send out SMS anymore.

The way SMS now works on 3CX has changed, and previous configurations will fail out of the box.

First, you will need to set up Telnyx with the new webhook located on the Trunk for Telnyx:



Update your Messaging Profile on Telnyx:



Add a DID to the user you want to send and receive SMS and add that number to the Inbound rules.

If after this, they can receive but they can’t send, and on the logs we can see either of these errors:

Failed to send message(s) to the provider 'telnyx' from '5559992223' to '+12223334444'. Exception: { "errors": [ { "code": "40305", "title": "Invalid 'from' address", "detail": "The 'from' address should be string containing a valid number associated with the sending messaging profile.", "meta": { "url": "https://developers.telnyx.com/docs/overview/errors/40305" } } ] }


Failed to send message(s) to the provider 'telnyx' from '5559992223' to '+12223334444'. Exception: { "errors": [ { "code": "40013", "title": "Invalid messaging source number", "detail": "The source phone number was deemed invalid by the carrier.", "meta": { "url": "https://developers.telnyx.com/docs/overview/errors/40013" } } ] }


Then check your Trunk DIDs. The client was on a 10-digit number basis (US/Canada), but they needed to have +1 appended to it on the Trunk in order for Telnyx to recognize the number as a source for SMS.




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