(Xbox One) What code do I need for invites?

I imagine this is a code issue; I can join other games and invite people I know on xbox one to play with me, but I can't invite them to my game? Do I need to add in certain code for xbox one in my game for xbox invites? Is this a code issue or an option issue or something? Some help on this would be greatly appreciated, sorry if this is posted in the wrong area.

The max players on my game is 10 so I know it isn't the player limit stopping me from inviting others :/.