I started on PS4, then changed to XBONE with game pass ultimate. Everything worked perfectly in the app when on PS4, and everything on XBONE with friends (parties, etc) works perfectly. When I join a fireteam in the app, I never get an invite. When I create a fireteam, the people I invite never get it. I've got every setting on XBONE to "allow", "everybody", etc. I've tried changing back and forth with "adult" and "custom" settings to no avail. I've restated my XBONE, uninstalled/reinstalled the app on my phone, signed out/signed in on both the phone app and my profile on the XBONE, I can go on. I cant figure out why this wont work on XBONE. Does it have something to do with me starting on PS4, so my linked accounts originated on PS4, then using the app to try to play XBONE fireteams? I make sure I sign in to the app as Xbox One and I ensure I have my system as XBONE when starting a fireteam or joining fireteams. Edit: I fire up my PS4, signed out of the mobile app and signed in as "Playstation". I joined a fireteam and got the invite within 10 seconds.