It has been fixed somehow, I can join my friend Realm again.Haven't been doing anything on my system to solve.
Weird, but confortable.
I'm experiencing the same problem on a Realms server belonging to a friend. Popping up, 20 to 30 seconds with no complex intercation, then disconnected. Far host forcibly disconnected my session, due to Internal Exception java.io.IOEexception.
Dumont Nicolas
It has been fixed somehow, I can join my friend Realm again.
Haven't been doing anything on my system to solve.
Weird, but confortable.