My son all of the sudden can't join his brother's realm - despite NO change to any Microsoft or xbox live privacy settings. The error code says "error - You cannot play online multiplayer through Xbox Live because of how your account is set up. This can be changed in your privacy & online safety settings on xbox.com". Again, he was joining the realm without issue and then one day something changed and he can't join the realm or accept the invitation. His settings were never changed - and when I went into his xbox live account, everything is in order to allow him to play. I've called Microsoft and Xbox Live twice and sat on the phone 90+ minutes each time trying to resolve this issue without any luck.