unable to connect to my matches "crash" game crashing

my screen keeps going black then it doesn't let me play at all it keeps saying I'm unable to connect to server and ot check my internet connection but my connection is just fine all other internet pages are fine but the game keeps crashing and I cant play leaguge of legends at all please help I also got a 10min leverbuster due to this issue so please fix this and walk me through how to do so opleasee