Freepbx version 18.104.22.168 Asterisk version 13.7.1
We have struggled with this problem for a long time. Can never seem to nail it down. We are using SIP trunks. Several times a day an outgoing call will not go through or will only last 5 - 10 seconds then get dropped. We have a Sonicwall between us and the ISP. The Sonicwall is not ours. For several years there was a Asterisk based system that worked fine in the same environment. I believe the asterisk version was 1.8. Today the customer called the SIP trunk provider and had several calls fail. The provider sent this to me:
BYE sip:email@example.com:5060 SIP/2.0
Via: SIP/2.0/UDP 22.214.171.124:5060;branch=z9hG4bK5ae80c83;rport
CSeq: 103 BYE
X-Asterisk-HangupCause: No user responding
I am going to start a tcpdump on the system to see if I can trap bad calls.