Hi all, I'm trying the example at http://trac.pjsip.org/repos/wiki/Python_SIP/Accounts The original version of "registration.py" works fine. But when I changed the line: transport = lib.create_transport(pj.TransportType.UDP) to transport = lib.create_transport(pj.TransportType.TCP) I got there error info. 17:11:44.396 pjsua_acc.c Unable to generate suitable Contact header for reg istration: Unsupported transport (PJSIP_EUNSUPTRANSPORT) [status=171060] 17:11:44.396 pjsua_acc.c Unable to create registration: Unsupported transpo rt (PJSIP_EUNSUPTRANSPORT) [status=171060] No package was sent out at all. What mistakes did I make?