If you have any devices Google Voice is forwarded to other than your Obi box, this could be your issue:
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Suddenly whenever anyone called my Google Voice line, my Obi200 would ring once, and then they get "Please leave your message for <my name>" (which isn't my default greeting).
I noted that now under "Phones/settings" for Google Voice (Legacy), under "Forward calls to:", it now has "OBiTALK device - <device#>" instead of "Google Chat". (Nothing about OBiTALK appears under Settings using the updated Google Voice UI).
If I uncheck that, the only difference is that my Obi200 would not ring even the single time, but the caller would still get the same message (instead of my normal greeting) after one ring.
I had no problems calling out, but being able to receive Google Voice calls via my Obi box is the most important function.
NOTED WORKAROUND: I also had Google Voice set to forward to my mobile phone, which is normally turned off. Once I turned it on, both it and the phone attached to my Obi200 rang normally, and I could answer the call. If I didn't answer, the caller got my normal greeting. However, when I powered down that phone again, it reverted to the prior behavior. As I expected, unchecking that mobile phone allowed calls to my Obi200 to ring normally and get the proper greeting if not answered.
This is a change from how Google Voice previously worked with this same setup. I first noted this issue a few days ago, but it may have occurred much earlier.
Even if you normally keep your cell phone on at all times, I suspect the effect would be the same if that cell phone happens to be out of range.