This problem started for me sometime last night with my Obi200 (which is connected to Google Voice); I noticed the phone indicator (right hand LED) was off this morning, and started Googling the problem, winding up on this thread. I've only had my Obi200 since August, and it was working fine up to now. I had set the device to automatically check for firmware updates by following the directions on this Obitalk webpage:
https://www.obitalk.com/info/faq/Troubleshooting-sec/How-do-I-automate-upgrades but apparently it had not actually been checking for updates, since my firmware version this morning was 3.1.1.5463. I tried forcing the update by dialing ***6, but the robot voice told me no updates were available, which I didn't believe based on earlier posts in this thread. I also looked at some Google results about manually updating the Obi's firmware, but in the Obi Expert configuration settings under System Management, there was no Device Update selection available, so that wouldn't have worked for me.
Anyway, in the Obi Expert menu I inadvertently clicked on the Revert to ObiTALK button, not realizing that it would remove my specific changes in Obi Expert, which were basically the settings for auto updating. When I realized that, I went back in and reset those selections. Then I noticed the Obi200 resetting itself a couple of times (the left hand LED going to red), and then it started working again. When I checked the firmware version (***0, then 1#) I discovered it had updated to 3.2.1.5757. Outgoing and incoming calls are working again, and the Anveo 911 test says that's all working as well.
Sorry to be so wordy, but I wanted to describe the things which were supposed to be working but weren't. It appears that a firmware update solved the problem for me. It's just that I couldn't initiate that update in the way that is supposed to work, and I'm not sure exactly what it was that I did that made it happen. And without that manual update option, I guess I'm going to have to pay Obihai after next August if I want to keep the Obi200 working.