Hello! I am using pjsua for my UA applications. In the case of INVITE message without the owner's SDP (Content-Length == 0) is not working correctly. In the case of an INVITE with no SDP, but with the plan/text (Content-Length > 0), it is not working correctly. Example: 2012-03-12 14:44:27.974 pjsua_core.c RX 337 bytes Request msg INVITE/cseq=314159 (rdata0x23db5c8) from UDP 192.168.23.48:36702: INVITE sip:bob at 192.168.23.48 SIP/2.0 Via: SIP/2.0/UDP 192.168.23.48:36702 Max-Forwards: 70 To: Bob <sip:bob at 192.168.23.48> From: Alice <sip:alice@xxxxxxxxxxx>;tag=1928301774 Call-ID: a84b4c76e66710 at pc33.atlanta.com CSeq: 314159 INVITE Contact: <sip:alice at pc33.atlanta.com> Content-Type: plain/text Content-Length: 11 test --end msg-- 2012-03-12 14:44:27.974 pjsua_call.c Incoming Request msg INVITE/cseq=314159 (rdata0x23db5c8) 2012-03-12 14:44:27.974 pjsua_call.c Bad SDP in incoming INVITE: Not Acceptable [status=170406] 2012-03-12 14:44:27.974 pjsua_core.c TX 291 bytes Response msg 400/INVITE/cseq=314159 (tdta0x23def90) to UDP 192.168.23.48:36702: SIP/2.0 400 Bad SDP Via: SIP/2.0/UDP 192.168.23.48:36702;received=192.168.23.48 Call-ID: a84b4c76e66710 at pc33.atlanta.com From: "Alice" <sip:alice@xxxxxxxxxxx>;tag=1928301774 To: "Bob" <sip:bob at 192.168.23.48> CSeq: 314159 INVITE Warning: 399 sky "Not Acceptable" Content-Length: 0 --end msg-- I think it is wrong.