Intermittent No Audio on Incoming Calls

Well, I seem to have irritated the FreePBX gods… Coincidence?..

Since yesterday morning, we lose incoming audio on about a quarter of our calls.

The calls come in from POTS (three lines) => GXP4104 => FreePBX 16.0.40.8 => Time Conditions => IVR => Ring Group.

Rebooted everything (router, GXP4101, FreePBX), no change. Everything up to date.

This has been our setup for years.

On the calls that fail, the caller can hear us, but we can’t hear the caller.

On one particular call, there was two-way audio when the call was picked up from the Ring Group, but the incoming audio disappeared upon transfer to another extension.

Any help is greatly appreciated, as always…

AND… As always, I would love to pay a phone guy a decent rate to help with these little problems. I charge for my time and I expect to pay for other people’s time. I tried buying tech support from Sangoma, but wasted $600 on expired credits - I am just too small an operation for a big tech service like that. If anyone is interested, please let me know.