Mac connection problem to the game

I believe that there are many players have the same problem with me, which is after champion select and turn into the game, it suddenly just become white screen and said "Unable to connect to the server. Please check your network connection and attempt to reconnect to your game." i have check everything and something i can restart and reconnect, but recently it just ridiculously dont let in go back in no matter i restart the MAC or the game, i start feeling frustrated about it, since it automatically cost me LP (Rank game) for the leave.