codered....I had the same problem with my first 721. The installer even came back to troubleshoot it. We finally declared it DOA.
I unplugged it and set it aside for a day, then hooked it back up only to have it act the same as before (and like yours is now).
I performed a NVM Reset, and just allowed it to do its thing...a little over an hour passed then a screen came up saying I was not authorized, I called and had it auth.......IT WORKS!!!!