Hi everyone, We're pretty new to the 3CX Fax Server feature and we can't seem to get this (simple) feature to work. All we need is for Fax to Email to work. I opened up a support case with 3CX and they state that the trunk provider will need to support T.38 on their end. I've confirmed with two of the three providers that we've tested with that they are T.38 capable, so far we've tested with CallCentric, Voip.ms (not T.38 capable), and BabyTel. We are on V15 SP3 (15.0.60903.0) Each time I test a fax, this is what I get in the Activity Log: 12/30/2016 1:19:30 PM - L:235.2[Fax:888] Sending: OnSendResp Send 488/INVITE from 0.0.0.0:0 tid=3164b524a509d23d Call-ID=MqXqt7y2QxZ_NfOSDRU1Xw..: SIP/2.0 488 Not Acceptable Here Via: SIP/2.0/UDP 127.0.0.1:5483;branch=z9hG4bK-524287-1---3164b524a509d23d;rport=5483 To: <sip:[Incoming Fax Number]@[Our 3CX FQDN]:5060;nf=e>;tag=e81e812a From: <sip:888@[Internal 3CX IP]:5060;user=fax>;tag=f258bf33 Call-ID: MqXqt7y2QxZ_NfOSDRU1Xw.. CSeq: 2 INVITE Content-Length: 0 Any input in this matter would be greatly appreciated.