I cant join a game

Everytime i join a game and enter the loading screen after champ select, my screen turns black and then a white box pops up saying unable to connect to server or something and then it gives me two boxes to choose from saying retry or cancel, eversince yesterday i couldn't join any games, the last three ended up in me not connecting and the game having to remake, i hope i dont get any low priority queue times over something i cant control i need help with this bug!