If your network uses legacy DART ad tags, you can use the TagShooter tool at TagShooter.com to figure out what's serving to your DART ad tags and why. You can use Tagshooter if you'd like to know why a particular ad isn't serving to an ad tag or why another ad is appearing in its place.
dcopt=istout-of-page ad call. As a consequence, you can't use Tagshooter to troubleshoot
dcopt=isttags for out-of-page ad calls.
To use TagShooter:
Check that you're already signed in to DoubleClick for Publishers.
Locate and copy the ad tag you want to troubleshoot. To find the tag on your page, right-click and select View page source, then press Ctrl+F. The tag should look like the following:http://ad.doubleclick.net/
N1234/ adj/ TopLevelAdUnit/ SecondLevelAdUnit; pos=top; sz=300x250; ord=123456?
In the upgraded version of DFP, top level ad units are analogous to DART sites, and second level ad units are analogous to DART zones. (Learn more about terminology differences.)
Paste the tag in the field above and click OPEN. You should be taken to the debug screen for that ad request. (See Reasons why a line item may not be serving for more information.)
Don't worry if you see a different ad; the TagShooter causes the ad server to restart the ad selection process, which may result in different ads being served due to creative rotation.
This tool is only for legacy DART tags. If you're using Google Publisher Tags (GPT), use the built-in console to troubleshoot.