Online Coop not working

Me and my friend have been trying to do Coop for any Halo. Every time we try to join it give us an error message that we could not connect. The Error is Connection Failed. then it says Your connection to the game session has failed please try again.

We put in the same live settings and we have even the same ISP. How can we fix this?

Maybe it’s a problem with Xbox Like have you checked support and troubleshooting on the Microsoft website.