Last evening I made a full system backup, and I am so glad I did. Today I checked for module updates and saw that there were updates for CDR Reports and for SIP Settings, and I updated both. Some time after I did that, I had a reason to reboot the system and then I found that no calls would complete, and while watching the CLI I saw the “no reply to our critical packet” error as described at http://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions
I rebooted again and the problem persisted, so I reverted to my backup and then everything worked great again. I then reinstalled the CDR Reports upgrade, and after that I rebooted the system just to make sure everything would still work, and it did. By process of elimination, that leads me to wonder if there is an issue with the SIP Settings module. Obviously I can’t be sure because any number of other things could have caused this, just coincidentally around the same time I updated these modules, so that’s why I’m asking if anyone else has seen this particular issue. I’m running FreePBX 12, Asterisk 11 (FreePBX DIstro but I doubt this is a Distro issue).
Even if no one else has this problem, there is a moral here: Having a very recent backup is really sweet when you encounter an issue such as this!