Black Screen after champ select!

I started a custom game and invited my friend, i started the game and chose my champ and it opened up the game as usual. Instead of showing the two champs opposite each other it just showed a black screen and said "Unable to connect to the server. Please check your network connection and attempt to reconnect to your game". I had played normal games before this so this only appears to happen in custom games and tried a full repair but it didn't work. Please Help! [zombie-brand-facepalm]

Edit: its in normal games as well :P