Multiplayer server: "Internal Exception: java.lang.ClassCastException: bit cannot cast to fm"

Every time i try and connect to specific servers, I get an error while connecting which either says
"Internal Exception: java.lang.ClassCastException: bit cannot cast to fm"

or "kicked while connecting to "server name". You are not logged in"

or it says "Internal Exception: java.lang.ClassCastException: bju cannot cast to fm"

Other people can connect to this server fine. I tried it on other accounts and it works, leading me to believe this is a problem with my account alone. I am not banned, or blocked from the server in anyway. Is there anyway to fix this so that I can play?

(Also i looked this up, the best option for a fix was change the render distance to 2, and put frame rate to max. I tried that and it didn't work.)