A friend created a Realm server for him, me, and other friend. They can enter and play without issues. But everytime I join the realm, after a few seconds, everything freezes and this error appears:

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

I've trying to reinstall MC and Java. Open ports of router. Using JAR client instead of .exe. Making MC to use the last version of Java. Everything was unsuccesful. The error still appears and I cant play with my friends.

I hope someone can tell me something, because this is getting too annoying.

Thank you for your time, and sorry if my english isnt very nice.
Bye!

PD: Im playing in the new version. 1.12