Minecraft error connection was closed by the remote host?

I want to play on a minecraft server but it always says: Internal error: connection was closed by the remote host what does this mean?

info on the edge: I reinstalled java, switched my Wi-Fi on and off.

Have you ever been there on Sever? They should delete your player data from the server. Somehow something is wrong, which is why the connection between you and the server does not work.

With Modpacks you have to have all mods and the correct versions. Launcher up to date?