As simple as the title. My roommate and I cannot join each other's fireteam. We both have Xbox One and are both on the same network (his is wired with an ethernet cable and mine is wireless). No matter who sends the invitation or where we are in the game, we get the message "Unable to join target player. Please try again." The problem started last Saturday. Before that, we were able to join and play without any problems. Has anyone else had this issue and/or found a solution?