3CX not sending received FAXes to email

[ben.meyer]

Hello,
I am new to 3CX.
I have successfully deployed 25 users on our corporate LAN with one SIP trunk. The product has worked reliably for 6 months since inception.
I am now trying to add a fax server so that all faxes received on a DID are forwarded to an email.
The default extension for the fax server is 88 (cannot be altered).
3CX answers on the DID and I can hear a fax modem answer. That is as far as I can succeed.
The calling fax machine reports an error. 3CX Call Log shows a talk time of 00:01:12 to "Fax(88)". There does not appear to be anything in the Activity log.
Did I miss anything out? I have configured settings/fax server with email/extension 88/DID. Advanced/Fax is empty as I do not have an external fax machine.
I am not sure what to look for in a Wireshark dump: nothing was obvious to me.

All help is much appreciated.

 

[eddv123]

Firstly confirm you have followed this guide here:
https://www.3cx.com/docs/manual/fax-server/

Next also ensure your provider supports T.38 FAXing (unless of course you are using G711 Passthrough). Who is your provider ?

Also a PCAP trace would be useful as well, I have similar issue recently where the FAX was leaving correctly but somewhere in the provider network it garbled it and was sending it out the other end as standard voice: https://www.3cx.com/docs/capture-network-traffic/

 

[JohnS_3CX]

Hi Ben,

Try to disable G.711 to T.38 fallback and see if the fax is received now.

 

[eddv123]

Try to disable G.711 to T.38 fallback and see if the fax is received now.

Is there any reason this has been recommended @JohnS_3CX I know the PBX states "Enable G.711 to T.38 Fallback [BETA] " and it has been in Beta for a while now, it would be good to understand the status.

 

[JohnS_3CX]

This is so it will try T.38 first if the provider supports it. As for the status, no further updates at the moment