Game Pigeon isn't working

I've had game pigeon downloaded for a while, but for some reason it is no longer working. When I click on a game which was sent to me, it prompts me to click on the game pigeon sticker above my keyboard, but clicking does nothing. Opening game pigeon on the app store doesn't help as well. I also tried deleting it, but holding down on the sticker doesn't make the little x show up where I would delete it, help!