Actually, my OBI is a 200. Quit working like many others after a couple of years in service. Got the "out of service". Couldn't make outgoing calls nor receive incoming. Here's what finally worked for me:
After diddling with the DNS changes, etc and not having it work I decided to go all out.
1. Removed my OBI from the dashboard.
2. Did a factory reset.
3. Added my OBI back to the dashboard.
4. Changed the DNS servers to 1.1.1.1 and 1.0.0.1 (my router DNSes had been changed to these earlier.
Now everything is working again. Can make outgoing calls, receive incoming calls which now ring.
Of course it's possible OBI and/or Google coincidently fixed everything at the same time I was doing all this and my changes didn't have anything to do with it
-jj