Allow and block ads
Why blocked ads are still showing up on the page
There may be a delay of up to 24 hours between the time you block any ad and the time that ad is no longer eligible to run on your site. This is true whether the ad has been previously approved or only implicitly allowed.
Note also that when you block an ad by advertiser URL or by ad category, you may still see that ad awaiting review in the Ad review center. Learn more about why blocked ads may still appear in the Ad review center.