Recently, I’ve come across strange 404 errors occurring on different posts across this blog. The errors used to occur sometimes only, but on the existing posts. These randomly produced errors were generated followed by the redirect to a non-existing page with a long-lengthy URL like below:{}

It seems like there is something wrong with the Google’s Doubleclick DART crawler that is trying to locate a specific nonexistent document (doubleclick/DARTIframe.html) on the website. I did some research on that and found the Doublclick DART crawler guilty for this – and also the solution to this error.

What exactly causes the doublick DARTIframe error?

Google Doubleclick DART crawler is supposed to be used for expandable or interstitial Google ads; and such type of technologies require permissions on websites via a simple file upload (similar to things we do to verify websites with services like Google Webmasters).

The error is produced when the DART crawler doesn’t find that specific file.

One more question though. Why do the crawler looks for that file? Well, here is the detailed answer:

All web browsers place restrictions on interaction between documents that reside on different domains. This is a security feature designed to prevent documents on one domain from reading data on another, using a scripting language like JavaScript.

Browser restrictions on cross-domain scripting in iframes are necessary to prevent malicious data access. The browser sees the document inside the iframe (the ad) as residing in a different domain from the surrounding page content.

When a website uses iframe ad tags, an iframe is created around the ad. For example, if has an iframe ad tag that displays an ad from, the ad is restricted from accessing anything outside the enclosing iframe. This restriction prevents Floating and Expanding creatives from being served through iframe ad tags.

However, there are cases, as with ads served by third parties, where publishers want to grant leave from the iframe environment to domains that they trust. Click to the next page for more details.
– From DoubleClick Rich Media iframe overview

You should look this problem seriously, as it may create a tons of 404 errors in your sites’ Google Webmaster tools dashboard, and there are chances that this may hurt it’s search rankings.

Doubleclick DARTIframe error: the FIX

Moving forward, the fix to this problem, as quoted by Google, is:

If your site uses iframes, you must download the DARTIframe.html file to successfully run Rich Media ads in your website.
As on this Google support page

The error doesn’t occur on all the sites using Google ads or AdSense. But it’s quite clear that you’ll need to implement the fix if you want Google ads to work properly on your site without creating such 404 errors.

Uploading Doubleclick DARTIframe.html

In order to fix this annoying error, just create a blank directory naming doubleclick in your website’s root. Now, download this zipped folder, extract the files, look for DARTIframe.html and upload it to the just created blank folder in the root of your site.


DoubleClick Rich Media iframe solution
DoubleClick Rich Media iframe solution: Notes
DARTIframe.html file