I’m running FreePBX 15.0.21 on a VULTR server (static IP.) We only have 15 extensions, along with three SIP trunks.
We’re having an INTERMITTENT issue when callers are placed on hold. After reception picks back up after hold, there is no longer any audio (or occasionally one way audio.) This has just started happening in the last two days. All of our SIP peers and trunks are legacy (not PJSIP). I’m not sure if that makes a difference, since it wasn’t doing it a few days ago.
The only change I made a few days ago was the QUALIFY FREQUENCY for each extension. We were getting REACHABLE / UNREACHABLE messages fairly often, so I adjusted the QUALIFY FREQUENCY to 30.
Other people have reported similar issues. However, qualify failures don’t affect calls in progress. On the other hand, they do indicate an unreliable network, so the loss of packets may be part of the problem. Even then, the worst I can imagine is that a re-INVITE back to direct media fails to take at the first, attempt, but that should resolve itself automatically.
So far, no-one reporting this effect has come back with the detailed protocol logging needed to understand what is really going on.
The adjustment to the QUALIFY FREQUENCY was really just to troubleshoot the REACHABLE / LAGGED / UNREACHABLE issues that we’ve been having. I’m not sure that they are affecting the no-audio-after-hold issue either.