If you shut down the OBi and run Gmail, can you receive GV calls there? If not, the problem is not OBi related; try GV support and/or forum.
Otherwise, shut down Gmail, bring up the OBi and make a (failing) test call to your GV number. Log directly into the OBi at the address reported by dialing ***1 and look at Call History. Report what, if anything, is logged for the failed call.