Hi Greg:
The OBiTALK portal had an extended outage this weekend that was apparently fixed today. That might have been causing your problem. You may just want to try again tomorrow.
Otherwise, this could be caused by your browser being signed into more than one Google account. Try signing out of all Google-related services, on all of your web browsers, then clear the browser's cache, cookies and history, close and reopen the browser, and sign in again to only the one Google account that holds your Google Voice number. Then, try the OBi setup again.