Sending Fax Failed

[Jt-o-it]

Hello,

we have a selfhosted 3CX Phonesystem V. 18.0 (Build 461)
the SIP-Trunks are registered and telephoning is possible.

Now we have the issue that even if we don't want to send a fax, we can't receive any either.
We followed the instruction of configuration where the faxnumber is set as DID to the Fax Server, we have set an email-adresse for receiving.

But everytime someone tries to send a fax to us, we won't receive any notification about it, and Sender got an error which says that the fax can't be delivered.

We have more than one SIP-Trunk regristered and more than one faxnumber as well. Could it be that the 3CX System can't handle more than one faxnumber on it's integratet Fax Server?

Did we miss any configuration step?

 

[Saqqara]

Do your sip provider supports fax protocols - T38

 

[Jt-o-it]

One of our provides supports the T.38 protocol

Is it necessary to support the T.38 protocol?

 

[Saqqara]

One of our provides supports the T.38 protocol

Is it necessary to support the T.38 protocol?

Yes, T38 is the fax protocol over IP - https://en.wikipedia.org/wiki/T.38

 

[Jt-o-it]

Yes, T38 is the fax protocol over IP - https://en.wikipedia.org/wiki/T.38

One of our prividers recomended using the G711 protocol as fax protocol
In the configuration of the 3CX it looks like they are supporting the G711 protocol as Fax protocol as well.

Many Thanks