Can not connect to server (long standing issue)

Hi there,

ive been trying to find a solution to this issue for a very long time (since release) and cannot find a solution.
me and my friend game share on Xbox one X. For every game we purchase, we can both play it. We’ve been doing this for years with no issues.
However while I can play this game with no issues (I’m the one who purchased it) my friend; whenever he tries to load the game, he gets a message saying that he’s ‘lost connection to Halo wars 2 servers’. Then it will connect, then disconnect with the same message every 5 seconds or so.
we’be tried everything to fix this. Clearing cache, hard reset, uninstall and reinstall, clearing saved data, deleting all DLC but still no luck.

If anyome has any way to fix this or has run into this before please let me know. I’d love to hear any and all solutions.

Please there must be someone out there who can shed even a little bit of light on this