Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host

When i try to join my Friend's Realm, i got kicked with the message :

Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host

Sometimes i manage to connect, and it randomly kicks me and sometimes i cant even connect to the server, i tried everything : Firewall, Ports, Reseting router, reinstalling MC, searching in the logs... but nothing worked, there is no problems when i connect to a public MC server in Multiplayer.