Instantly getting kicked whilst connecting to Server

Hello everyone,

I'm currently in the work of an Bungeecord Server but I'm running into an very big problem, which i have no clue on how to fix it.

Heres the problem:

I want to join an Minigame Server, but when i try to join, it instantly kicks me leaving no Error in the Server's, but in the Bungeecord's console. (Joining the Hub works perfectly fine)
It just disconnects me with the Message: "internal exception java.io.ioexception an existing connection was forcibly closed by the host"...

Instantly getting kicked whilst connecting to Server