I just tried one thing, it seemed worked. So I am suggesting you try too.
Because the message mentioned about service provider, I wanted to check my service provider, even though I knew mine is google voice.
I logged in the obitalk website, and under
"Approved Service Providers" -> "For Home",
you will see list of things to the right hand side. On top of them is "Google Voice". There is a little blue button "Setup Now" right to it. Even though I thought it should have already been setup, I clicked it anyways, and sure enough, there was something came up, and they system was running. When it's done, I tried again, the phone now works.
So my guess is some how now you need to manually select your service provider in your account now, and the whole system needs to be setup at Obitalk's system again.
For the ones with other service provider, I would suggest to follow the instruction displayed on the web (below the google Voice choice).