Hi all,
I found that some of my faxes failed to be sent/received bcz remote PBX drop the calls after my FreeSWITCH send empty (without SDP) 200 OK message on received re-invite from remote party while sending or receiving fax with T.38.
CLIENT > INVITE (G.711) > FS
FS > 200 OK > CLIENT
CLIENT > INVITE (T.38) > FS
FS > 200 OK > CLEINT
...
now receiving fax
while fax is received, client send me reinvite with the same SDP T.38 details as in initial T.38 INVITE message. usually it happens after 900 or 1800 seconds - probably it kind of keepalive...