Board Thread:Game Discussion/@comment-176.221.120.73-20170624134541/@comment-29605676-20180206133901

MoisesGabby wrote: If the ads get "stuck," and the button stops working. Close the game and reset ad ID, and the ads will come back. On Android it is in settings > Google > Ads > Reset Advertising ID. IOS is something similar.

On iOS Settings -> Privacy ->Advertising, and here you should see an option to reset ad ID. As MoisesGabby said, you need to do this when the button stops working or it disappears. Also I have found you might need to do this more than once on rate occasions.

The other thing is that you need to reset the ad ID after you have closed/force quitted the game. I think the game looks for the info each time you start the app.