If any of your ads aren't delivering as expected, and you followed the steps outlined in the article, Line item isn't delivering ads, you can check your live pages for Legacy DFP tags to see if they're set up correctly. For a line item to be eligible to serve to a particular ad slot, that ad tag's ad unit, sizes and key-values must fulfill that line item's targeting criteria.
You can paste the tag into TagShooter to see which line item are or are not eligible to serve to that tag and why.
Follow these steps to find the Legacy DFP ad tags on your page:
Open any browser and navigate to the live URL to which the ad should be serving.
Right-click on the page and select View source or View page source.
Use Ctrl+f (the text search function shortcut) to search for the text "
If there are multiple DoubleClick ad tags on the page, scroll to the ad slot in question, as determined by size and key-values.
The ad tag can be found in the quotation marks following
href=. It begins with
http://ad.doubleclick.netand ends with