Fax Server failures

[Megan]

We've got a Fax Server to email setup not working. Calls to the line get fax tone, but faxes themselves to it all fail. Setup and test details as follows:

• Running Professional Annual v. 16.0.3.676
• Line provider for the SIP originally noted line was configured for G711, 726 , and 729 but T38 is was not enabled
• At that time we couldn't even get fax tone when dialing
• We had line provider enable T38 and after that we were immediately able to get fax tone when calling
• We then faxing tried with "Enable G.711 to T.38 Fallback [BETA]" turned off and on, both tests failed with an error citing the line as busy
• We confirmed the line in question wasn't actually busy during either test phase and nothing is coming across the the fax to email setup

Anyone face a similar issue by chance?

 

[eddv123]

Yeah quite a few times, but mostly it was provider related issues that caused it.

With that being said I had to do some thorough Wireshark tracing (proving) in order to get them to listen and make changes.

 

[Doberman_techAJ]

Yeah quite a few times, but mostly it was provider related issues that caused it.

With that being said I had to do some thorough Wireshark tracing (proving) in order to get them to listen and make changes.

What wound up being the resolution on this? The provider we are dealing with is not necessarily a large provider.

 

[eddv123]

What wound up being the resolution on this?

Basically I was able to trace the 3CX (FAX sending system), the attached trunk (Twilio in this case) and the 3CX at the other end (receiving FAX) and show that FAX was sending fine in these areas and that on the receiving FAX it was emerging as a VoIP call not FAX.

Once they saw the evidence they went and changed something on their internal network and it worked.