Grandstream BT200 extensions no longer ring after upgrade to v2.9

We just upgraded to v2.9.0.7 and we have a Ring Group with two extensions on it and another extension by itself (no ring group) at another location. They are all Grandstream BT200’s and have the most recent firmware.

Since the upgrade, the phones will not receive any calls and do not ring but instead go straight to voicemail. I have tried power them down and then back up. I have tried making sure Call Forward is off and that DND is deactivated.

Sometimes, the phones on the Ring Group will work for the very first call they receive after powering them up, but after that they no longer receive any more calls.

Softphones seem to be unaffected and still work fine.

Anybody have any ideas or thoughts what might be going on?