Asterisk,SIP Retransmission timeout

Question

I have created a sip trunk from One Asterisk(version 11.2.1) say \'A\' server to another Asterisk server(11.7.0) say \'B\', and I am getting sip response 200 ok.
But when I

Answer 1

make sure you have correct ip address in 'externip=' in sip.conf under /etc/asterisk.