Disconnected from server (.300)

[Hakkuryuu]

Im sure someone already wrote about this issue but I couldn't find any way to solve it, so if you have any solutions please feel free to tell me.
So here is the problem : I start the game ( Na Region ) insert my pin and create my character. Untill now no problems but after I want to start the game and enter a server it tells me shortly after that I "disconnected from server (.300)" after that the game closes and leaves me behind with nothing but sadness.