How do I fix a game if it’s not compatible

You can't. If you have an Xbox One S and the game is for the Series S|X, you'll need to buy the latest console or request a refund if you have already purchased an incompatible game.

The same applies the other way around too. If a Xbox 360 game is not backward compatible, then there is nothing that can be done to play the game on the Xbox One or Series X|S.

When it's listed as S/X, it's referring to the Series S/X not the One. If there is a One version of the games you're wanting to play, you would need to make sure to get that version of the game, not the Series S/X version.

The One version of Hogwarts Legacy is currently available for preorder and will release on April 4.

Hi! I'm Luis, a fellow Xbox Gamer . Thanks for reaching us out here.

That is most likely due to Activision shutting down all media uploads due to all the mod infections that are on black ops 2

Have you tried any other backwards compatible Xbox games?

It could be the backwards compatibility software that is corrupt, although I have no clue how you would fix that if it is.