Thanks for the info Steve. I checked the site that I was logging into and it was the correct bev.myford site. Still not sure why it will not accept then VIN.
I had problems registering my car via windows PC. When I tried using the Ford Android app it worked. The other option is to use a different PC when registering the car.
This thread answers another question for me: how does the mobile app communicate with the car? Apparently it's via an AT&T cell modem. So your car needs to be in a coverage area for the app to work.