2 problems.

Hello, I have 2 problems with Halo MCC.
When I join a friend to play matchmaking a error message pops up saying - “Data out of sync. Your data does not match the hosts. Please download the latest data by restarting the game and rejoining the party.”
I have done exactly as it says but the problem remains.

The second problem is that I can’t download the Halo 5 MP Beta as it is not highlighted under “Extras”, I cant press it.

I have spoken to the Xbox support through chat and I received a reference number which is 1274735477 , the person linked me here and told me to post in the forum.