Alright this is a question I’ve had for about 4 months now, I gave up with it seeing if it’s been fixed but apparently it hasn’t. I bought FH when it came out for $60 usd and now it’s saying when I download it that “disc can not be read” it’s a dlc not a disc. Is that a mircosoft issue or a Turn10/Playground games issue? I’m unable and unwanting to put another $20 into buying a disc as I bought and own the DLC. Anything will help 
It is a digital rights management issue - you will need to contact MS to get to help you sort it out (there used to be a post on the old forums with how to fix it but it is gone now).