owning a digital copy and xbox game pass ultimate, play together (simultaneously)

Both are purchased on my account, my son is set up under the family settings. This has worked fine for the past year, unless there was a tos change, why would this happen now?

edit: the digital version was the play anywhere version and it was gamepass ultimate,so that can rule out any issue with either of those.

Is the account wih the digital version set as home Xbox or bought on his account?

Each console would need their own copy of the game and a separate subscription to Xbox Live as well to be able to play together simultaneously

The digital copy is very convenient, even for those like me who own two xboxes and want to play together with the same game. But I'm a collector and I like physical copies... In fact, my wife gave me a digital copy of Sea of Thieves to play together.

Kindly check the status of your subscription by signing in at account.microsoft.com/services to make sure it's already active.

Also, It will only ask you to get Xbox game pass Ultimate if the games you're trying to play are previously played via game pass or if you don't own the digital/disc copy.