voice toubleshooting

Using the newest xfinity modem (xb8 I believe) in bridge mode and xfinity voice has worked fine.  I can make a voice call out but as of yesterday I cannot answer incoming calls.  I see them coming in but I cannot connect the call (tried on both direct connect handsets and wireless handsets).  I press 'talk' or pick up the handset and there is no one there.  On the other end the call keeps ringing.  Eventually the caller gets a 'the call cannot be completed as the call's party is temporarily unavailable' and it doesn't roll to voicemail.  If I leave the phone off the hook then the caller immediately rolls to voicemail.

I have rebooted my modem multiple times with no change.  Internet works fine and the modem light is solid white as it should be.