Failed to connect to server

Hello, i have visited this site before and i have seen that many people had the same problem that i'm currently having. I am trying to join my friend's server which is online, on the right version, normal vanilla server with not many plug-ins and my friends are playing in it right now but it won't let me join. I tried using both the server IP and the DynIP and neither the icon or server info pop up in my server list and the message it displays is : "Failed to connect to server" and "Connection timed out: no further information" while my friends can join without any problems. Please tell me what other way i could use to fix this problem and thank you.