Cant create open game lobby (MCC PC)

Hello, I've been struggling with an issue for some time now. For some reason, I am not able to set my game session type to open in Halo MCC on PC. If I click on the person icon in the top right, then click "My Game Session", the only two options I have for "Privacy" are "Invite Only" and "Friends Only". Everyone else I have talked to has an option to allow anyone to join their game session. I've joined on people by just searching up their username and clicking join. However, when I host lobbies people are not able to join me unless I invite them.

I have searched and searched for a setting to change this, both in the MCC game and on the Xbox Console companion app. I haven't found a way to allow myself to create open game session lobbies. Can someone help me with this?

I bought this game through Steam. Is it possible that there is a Steam setting I need to change?

1 month later and I am still faced with this problem (I have had this issue since I bought the game, but only posted for help last month). I have found nothing on Google that solves my issue and I have looked extensively. Does anyone have any ideas? It would be nice to get some insight from any staff who know how this game feature actually functions internally, as they might have a better idea as to what is causing it.