Black screen/unable to connect to servers

i have been experiencing this problem. i dont know if its only me or if other people are experiencing it too. i would load up a game and pick my champion. after that it goes black and says "unable to connect to servers. check your internet" or something along those lines. i have been having this trouble for 3 days now and i finally come to riot to fix it. i have been trying not to get leaver buster so the first time i got it i never did it on PvP again. instead i went to custom. Someone please help me with this.