Having trouble with Asterisk 11.7.0 and T.38 passthrough to a Grandstream HT502 ATA. Both Asterisk and the ATA are behind NAT. The Grandstream is set to receive T.38. SIP trunk carrier is Flowroute.
Some fax messages get through, some don’t. I seem to get the following error no matter what:
[Jan 20 04:09:47] WARNING[C-00000022]: chan_sip.c:10353 process_sdp: Failed to initialize UDPTL, declining image stream
[Jan 20 04:09:47] WARNING[C-00000022]: chan_sip.c:10506 process_sdp: Failing due to no acceptable offer found
Anyone know what this error means?