I have three accounts for my kids. All three can chat with each other over LAN, as well as on a Realm. Two of them can chat with other users on Realms. But one user is not able to see other users' chat messages, and other users can't see its chat messages. This is a problem for that user's friends and for users that aren't contacts.

This is occurring on mobile (Android 5.1.1) and Windows 10. I assume it has something to do with the user itself, but after looking at the settings, I can't figure out what.

Let me know if I can provide more info to help figure out what the problem is.