Tx Shale. My problem is resolved.
It had nothing to do with GV. It was simply that the Obi was unable to be reached from the server. I discovered the "self troubleshooting" link and followed that. It said
1) Dial ***6 and update firmware if available. I did that and there was an update available, but updating did not solve the problem.
2) Dial ***1 to obtain the IP address of the Obi (it speaks the IPv4 into your ear).
2a) Use a browser to connect to this IP and you will get a web page.
WRONG! You will be prompted for a login and password, which is not given by the troubleshooting guide. I guessed a few times and got it: "admin" and "admin". That got me in.
2b) Set the Obi's DNS to 188.8.131.52 (a public DNS server).
Then it worked.
I guess this VoIP stuff isn't exactly "just plug it in and go". I mean, they could config the DNS in the factory for you, but they don't. That means your DHCP has to serve the device a DNS that will work for it, and apparently that didn't happen.