Third-party creative isn't delivering
If you have a line item with a third-party creative that isn't delivering, there is either a problem with the third-party code or with the DoubleClick ad server. A good way to figure out where the problem lies is to install a free third-party application called Fiddler (requires Windows) and use it to check the requests sent from your browser to the ad server and from the ad server to the third-party.
The creative isn't delivering at all
Learn how to use Fiddler to troubleshoot creatives that aren't delivering at all.
The creative is blank or isn't rendering properly
If the line item is serving blanks or the creative isn't rendering properly, you can use Fiddler to inspect ad calls made from the DoubleClick ad server to the third party and create a test page to see if the creative renders properly when DFP isn't involved.
To use Fiddler to inspect ad calls to the third-party:
Open a browser and then open the web page where the line item isn't delivering properly.
Fiddler displays the list of requests made by your browser.
In the Web Sessions pane on the left side, look for the ad tag that's requesting the third-party creative.
Here's an example of what the requests will look like:
# Result Protocol Host URL 81 200 HTTP ads.thirdparty.com /adserving/getAd.jsp?PlacementId=123456&cm=456777 154 200 HTTP ads.thirdparty.com /adserving/getAd.jsp?PlacementId=123456&cm=456777 303 200 HTTP ads.thirdparty.com /adserving/getAd.jsp?PlacementId=123456&cm=456777
Successful requests to the DoubleClick ad server are indicated by the number 200 displayed in the Result column. If the request is successful, continue to Step 4. If it's unsuccessful, the problem may be with the DoubleClick ad server. See If the creative isn't delivering at all, above.
Identify which third party is serving the creative:
In Fiddler's Web Sessions pane, click the ad tag that's requesting the third-party creative.
Click the Inspectors tab on the top-right pane.
Below the Inspectors tab, click the Headers tab.
In the bottom-right pane, click the Text View tab.
You’ll see a message that says “Response is encoded and may need to be decoded before inspection.” Click on that message.
The creative code that the ad server returned to this ad tag on your page displays.
Look through the creative code and identify which third party is being called by the ad tag.
In Fiddler's Web Sessions pane, look in the Host column for call to the third party.
Successful calls to the third party are indicated by the number 200 displayed in the Result column. If DFP was able to make a successful call to the third party, that means that DFP is calling the ad tag correctly. If the creative is still not showing properly, then the creative code on the third party's side is broken in some way. Send the creative code to your advertiser so they can work with their third party creative developer to fix the code.
If a number other than 200 displays, then DFP isn't able to make a successful call to the third party. Create a test page to see if the creative is broken even when DFP isn't involved (see Use Fiddler to troubleshoot creatives that aren't delivering properly to learn how). You can then take a screenshot of the test page and send it to the advertiser so that they can send it to their third party creative developer.