In the OBi, the AuthUserName should be 1777xxxxxxx (replace xxxxxxx with last 7 digits of CC number).
AuthPassword must match what you enter for Phone password on the CC Preferences page, General tab. You cannot view the password, so if you're not sure, click edit and re-enter it. Leave URI at default.
If you still have trouble, report make/model of modem and separate router, if any.