Chat doesnt work between two players

I cannot see anything that a specific friend types.
The only time i see what he types is if he uses the command /tell , but this only works in creative.

I can see what other players type, and my friend can see what i type.

This is true for both Android to Android, Windows10 to Android and Windows10 to windows10 clients.
Both in realms and when I create a local server.