Can't join other players

Hi! Me and my brother recently got Xbox Game Pass and downloaded the MCC Collection wanting to throw it back to the good times of Halo. We loaded it up, got all of our settings setup, added each other on Xbox and went to join each other. No matter what we do or how we join we always get an instant “Unable to join” message basically. We’ve been searching for answers for about a day and we both have found nothing. Halo community please help me!

I think there is a problem since yesterday.
The matchmaking now works properly?

See also the Official Halosupport account in Twitter.

Yep, this is part of a known issue right now and 343 are working on a hotfix
https://www.halowaypoint.com/en-us/forums/85d779d52cfd46918b4f8b638f2e3c7b/topics/known-issue-season-7-update-matchmaking-errors/7e6c2cc6-6e80-4efd-9d24-8ec550019a27/posts?page=1

You can follow the Halo Support twitter for further information, or the thread a linked above
https://twitter.com/HaloSupport/status/1408117836069806083

> We have identified an underlying issue causing the “Leaving matchmaking…” issues preventing some players from joining matches. The team is working on a hotfix to resolve this issue as quickly as possible.