Whats wrong with my bunggecord server? Can anyone help me ?

Can any one help me ?
I created my own bunggecord server....
And then when i try to join my other server. I cant join it. It says "the server is not exist"
And sometimes it says "io.netty.channel and blah blah .... " i tired searching it on google and youtube but i cant find something clue for this problem ..