GameCenter not connecting with the game

I used to play simcity bulidit on my iphone(ios8) and after some time i uninstalled that game.......After some time i reinstalled that game(ios9) but the game is not connecting with the gamecenter as because there is no pop up (gamecenter) coming while starting the game and the progress and the points which i made on gc has lost too,How to restore that progress again???