Forza Not Working!!!

I’m posting for my friend. He recently got an Xbox One that came with Forza. He was playing it loads and unlocked online. When he did he went off Forza and on a different game. When he tried to go back on Forza it took him to the store. Please help!

Does he own the disc or is it digital
If digital did he use his account to buy it
Did he buy new or second hand
If he owns the disc was it in the console when he tried to play it …it will go to the store if the disc isnt in