...And there is nothing to be done. This is happening on both my iPad and IPhone. I have deleted the app and reinstalled on both, that did not work. Rebooted both devices, that didn’t work. I am not sure what happened, but I cannot access the app at all.
Update 3:39 pm 12/7/17: it appears the problem is with the Apple Game Center interface. If I open the app while logged into Game Center, it crashes. If I log into Game Center with the app already open, it crashes when I click “Online.” So I cannot play my online games that I have going with my friends until the bug is fixed or until I time out of the games. Sorry, friends!