Try clearing your browser cache (seriously).
Fact is, AdSense doesn’t always work, on ANY browser, or in every spot on a page. This is because a certain type of ad may be served, that fails to render.
If you Google this behavior, you will see common complaints going back to 2010 “why don’t my adsense ads load in Chrome,” “why don’t my adsense ads load in Safari” – etc.
The ONLY solution to this we found on some of our news portals (we have been using Adsense since it launched in beta, btw), is to serve up “text only” ads in certain spots.
This is because some advertisers with rich media, whether HTML5 animations, javascript animation, even old Flash ads (which I think are all gone now?), may time out, if loaded from the actual origin server (meaning they are not loading on Google’s cloud, but the actual advertiser content system/CDN). So, when it times out, nothing shows up.
Turning of ‘lazy loading’ completely for the theme, plugins, etc., can help also.
Used to annoy me to see blank ads in places.
Now I will say, I did have a day last week, where going to my own sites on Safari/iOS9/iPad Air, all the ad spots were blank, but they worked in Chrome. So, there be gremlins afoot!
But put another way, it’s NOT theme related — all the ad spots do is inject the code for Google to fetch and render the “spot” — if it times out, nothing fills the spot.
