Certain ads are obscuring the close button

I have encountered this 'Line Puzzle String Art' ad twice now and each time I had to hit the close button 3 times to close the ad. I never had trouble with other ads, so maybe this ad had has some kind of transparent overlay on the close button, or they made the clickable area really small.

Edit: some people mentioned you can get around this on Android by hitting the Back button. (I'm on iOS unfortunately)