session failed party server denied your connection

[Knighter_NSW]

Two days ago I on nintendo was able to co op with my xbox friend. Now we are both experiencing session failed party server denied your connection.

[GoodboyDior_PSN]

This same thing happened to me last year and now it’s happening right now. I was really hoping they would’ve fixed this. I know last year I heard it had to do with T-Mobile internet.