DC and can't reconnect, lost lp, kinda miffed

So everything goes smoothly through champ select but when it closes the screen goes black right before the game loading screen and I get the error message "Cannot connect to server" with the options "retry" and "close." Retry just has it go back to black and then pop up with the same message. I have tried restarting my computer and it still comes up with the same message. Eventually I just get sent back to main Client page with the Leaver penalties.