Anonymous Webmaster asks…
Several of the Google AdSense ads on our site are showing a “page not found” error within the ad space. I have checked from multiple locations and still see the errors. Our ads are not showing in all cases. Can you advise as to how I can correct?
This error had been puzzling me until recently when I saw the problem on one of my own sites and had to do some debugging. The answer starts with Google AdSense Alternative Ads, which provides a way to display your own ads if Google cannot display an ad on your page:
Alternate ads allow you to utilize your ad space in the event that Google is unable to serve targeted ads to your page. By default, Google shows public service ads (PSAs) if no targeted ads are available.
To display an altnernate ad, users are instructed to specify a URL pointing to their alternate ad resource, which looks this way inside the AdSense code:
google_alternate_ad_url = http://www.example.com/docs/alternatead.html;
A further advanced feature allows webmasters to collapse their ad if there are no targeted ads available so that it takes up no page space. This URL is given as an example:
I discovered that in my haste, I had copied the example above and replaced “example.com” with my own site name. That should work, right? Nooo… because I left the directory “/scripts/” in the path which made it point to a dead file instead of “google_adsense_script.html,” which lay in my root directory.
To answer the original question, if you are seeing the ”page not found error” inside your AdSense units, it is likely caused by an invalid alternative ads path. Make sure your alternate ads URL path is pointing to the correct file location.
Remember that the page not found error only appears when Google cannot display an ad. It is difficult to test your fix because most of the time Google displays ads. If it displays an ad, it’s not looking for the alternative ad path and therefore not showing the error. ¿Comprende?
Update: I have just discovered another way that the path gets messed up. When downloading the Google AdSense collapsing ad units script, Internet Explorer 7 truncates the file name by removing the “l” from the “.html” so this file:
Is saved on your desktop as this:
Guess which browser I am using