Unable to connect during loading screen

I'm not sure if anyone else has had this problem because i can't seen to find anything on it. But During loading into the game my screen goes black then after about a minute of waiting it has a pop up that says. "Unable to connect to server. Please check your network connection and try again." And it is not a firewall issue it has something to do with riot servers not communicating with my internet because I can log on to league just fine.