it’s possible for you to know what triggers the issue and the way to fix it.
Then why does the Xbox One backwards compatibility not working error appear?
Try the following methods.

To check that that the game you are trying to play is indeed backward compatible, kindly visitthis link.
Remember to find your exact version.
Compatibility features do not always support Deluxe Edition, GOTY Edition, and Special Edition games.

Related post:Cant Sign into Xbox One?
How to Get It Online?
A Guide for You!
Just check the above link regularly to see if there is any progress.
Therefore, you might attempt to perform a power-cycle.
Here is how to do that: