I've been doing some searching, but haven't been able to find a problem like mine. Maybe my Google-fu isn't as strong as I thought it was.
A couple weeks ago I lost service with my Obi 200 and Google Voice. Not sure what happened, but I deleted and setup the device again. Everything is back in business except my phones answering machine.
Until the service interruption, if anyone called our GV number, the answering machine would pick-up. Now however, when the answering machine picks up, you hear the normal greeting followed by a dial tone on the machine and the caller is forwarded to the GV voicemail system. The caller doesn't hear the answering machine greeting but does hear the GV greeting.
tl;dr
Can receive/send calls through OBi. Local answering machine picks up but only has dial tone after greeting. Caller is forwarded to GV voicemail and can't tell anything is wrong.