I have the war games pass and have downloaded the crimson map pack.
The content loaded no problems.
When I go to play the Infinity \ War Games \ Crimson DLC it will search for players, put me in a group, choose the teams, vote on the map and then start to load the content. It then kicks me out of the group and says everyone left the game.
It will then restart the search and continue this process over and over.
It will sometimes look as if it loading (the blue UNSC logo) and then actually kick me back to the start screen.
I have tried deleting the war games pass and the map pack and re-installed but it still continues to do this.
I can play any other game type and any other map no problems with no connection issues at all.