This appears to be a Google XMPP-related outage. Please post your exact, detailed symptoms on the GV help forum, in this thread:
https://productforums.google.com/d/topic/voice/orGScGDnsgg/discussion sop Google Engineering can take a look. Be sure to post from the same Google account that has the problem, and include the last 4 digits of your GV telephone number, so they can view your logs.
Posting here in the OBi forum won't get you any assistance.
Edit: Google Engineering is now looking into this -- I have no information as to when it will be fixed.