I will join a server for around a minute before being kicked out to the main menu with nothing but "Timed out" to inform about what happened. While playing (usually right before I get kicked), NPCs will stutter and jump around, and parts of the world will be invisible as though it isn't communicating with the server.

Another error sometimes shown is Java throwing an exception:

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