Hi, I use Kamailio as a stateless proxy with UDP + TCP. When TCP is used, I get the following TCP errors: WARNING: <core> [receive.c:265]: receive_msg(): error while trying onreply script ERROR: <core> [tcp_main.c:4338]: tcpconn_main_timeout(): connect xxxxxxxxx failed (timeout) WARNING: <core> [receive.c:265]: receive_msg(): error while trying onreply script ERROR: <core> [tcp_main.c:4338]: tcpconn_main_timeout(): connect xxxxxxxxxx failed (timeout) The TCP config in my script: tcp_connection_lifetime=3605 I get this issue when I receive replies to INVITE from the UAS. I can see the replies using ngrep but Kamailio doesn't seem to be able to process them correctly. I precise that the UAS is behind NAT and NAT configuration is correct (the INVITE does reach the UAS). I also precise that the UAS sends keepalive every 5 sec (I can see the ping-pong using ngrep). I set it to 5 sec to eliminate the possibility that the NAT closes the connection. Thanks, Mickael