Hi all, It looks like there is a bug in PJSIP, but I've submitted a bug in Asterisk tracker as I'm not sure if it occurs only in connection with res_pjsip or as stand-alone as well. Basically, when an endpoint registers via TCP, PJSIP processes everything as corresponds: the communication is via TCP, REGISTER/ACK pass OK, the endpoint can even establish calls. But, when another endpoint calls to the first one, PJSIP tries to send INVITE message in a new TCP session establishing it to the port already opened for the first session. This would be OK for a UDP, but not for TCP. Please let me know if you observe the same behavior without asterisk as well. For more information please check the bug report here: https://issues.asterisk.org/jira/browse/ASTERISK-24889. Regards, Anatoli
