You use it Google AdSense for creation revenue on your website, and sometimes ads are not showing on one or more pages?
This is likely because Google AdSense is unable to find advertisers willing to bid on σελίδα you at that moment. Or you may have blocked certain categories of advertisers from bidding on your page. Also if your page is updated daily, very old posts may not show ads but blanks instead of ads.
Here's a page with one advertising of Google AdSense placed somewhere in the middle of the page.
And below is the same page, but the ad has been replaced with a space.
In background
When any Google AdSense ad unit on your site sends an ad request to Google Servers, the AdSense server responds with an ad or sets the ad unit status to unfilled, which means there are no ads for viewing at that time.
If you do not want to see gaps in your site due to the unavailability of ads, you can hide unfilled ad units with CSS.
Open the main CSS of your website or the custom you use and add the following CSS code:
ins.adsbygoogle [data-ad-status = 'unfilled'] {display: none! important; }
From now on, if there are vacancies for ads on your site, they will not appear. You might also consider replacing the incomplete AdSense ad unit with an alternative image that links internally to one of your pages.