I'm puzzled, because a 401 means that the OBi did successfully contact the server and got an explicit "unauthorized" response. If you typed the credentials manually, try pasting them to avoid error. Be sure that what you paste does not have e.g. a space before or after the number or password.
If no luck, try registering a softphone to VOIPo. If that fails, too, I believe that only VOIPo support will be able to help. If the softphone works, you might try SIP Debug to see whether the OBi is sending your credentials properly.