Need Help with Private Server

I recently created my own private Grand Chase season 2 server, following all directions correctly from a video on YouTube that jmans25 created here:


It's very comprehensive and easy to follow and I managed to get everything working until I came to the server list and clicked on my server only to get "the server is not responding. Connection has timed out". Can anyone help me out with this? Thanks and Happy Holidays to everyone!

I'm not sure for 'server not responding" thing and "connection has timed out" but it seems to be that the network isn't fully established. I'm not a network architect but I know little something about networking.