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Troubleshoot unfilled impressions

An unfilled impression, or blank ad, is an ad request that didn’t return an ad. It means that no ad was eligible to serve. This can usually be avoided by having some widely targeted (run of network) ads like House ads or Ad Exchange ads always running in your network.

These are some of the main reasons for unfilled impressions:

No backup remnant ads trafficked to the inventory

The most common mistake that results in line items not being served is when tags are correctly implemented on your webpage but:

  • There are no paying line items that meet the user’s criteria.
  • A house line item (or other catch-all remnant line item type like Ad Exchange) has not been booked for the ad unit’s size.

This oversight can occur when new ad unit sizes are created and there are no house line items of this size. When the paying line items targeted to these ad units have reached their intra-day cap, a house line item will take the remnant inventory. If no house line items are booked, the result is an unfilled impression, or a blank ad.

Users who have disabled JavaScript won’t see custom creatives, so ensure that the house line item uses a standard GIF or JPG creative.

To avoid this problem:

  • Book a run-of-network house line item (or other catch-all remnant line item type like Ad Exchange) for every possible ad unit size.
    Why: When any new ad units are created, these line items will be targeted to run on them.
  • Traffic as many creatives in these house line items as there are same-size tiled ad slots in a webpage (you don’t need to do this for Ad Exchange line items because Ad Exchange creatives can serve to multiple slots on the same page).
    Why: DFP prevents the same creative from being served to a webpage. For example:
    1. There are two 728 x 90 ad tags in a webpage and only one 728 x 90 creative in the house line item that can be served to it.
    2. A creative from the house line item is served to the first ad tag.
    3. There’s nothing available to serve to the second ad tag, so the result is an unfilled impression.

Line items trafficked to the inventory aren’t serving

The best way to investigate why a particular ad slot is blank is to:

  1. Run the Delivery Inspector on your page.
  2. Find the slots that were unfilled and run the Ad Request Simulator on those slots.
  3. Search for the line items you would expect to serve to this slot to understand why they aren’t serving.
  4. Look at the reason the line item didn’t win this particular simulation and also the historical non-delivery reasons. These are surfaced both in the Ad Request Simulator when you search for a line item, and also on the line item’s “Troubleshoot” tab.
    If the Ad Request Simulator shows the message “Line item not found,” this typically means that the line item is not targeting as expected or is not serving. See below for examples of why this might occur.
  5. Depending on the reason a particular line item isn’t serving, you’ll need to adjust a setting on that line item or other line items. See below for examples.

Line item targeting

  • For line items to serve, they must be properly targeted to the ad tag.
    1. A line item is targeting a key-value.
    2. The key-value isn't in the ad tag.
    3. The line item doesn't serve to that tag.
    4. Troubleshoot:
      1. Review any line items you believe should be serving to this tag.
      2. Check whether they match what’s on the page.
  • If the blank ad unit is designated as special, traffickers must specifically target it, even if it’s in a level below an ad unit that’s been targeted.
    Why: No line item will serve to special ad units unless those ad units are specifically targeted.

Line item status

  • Line items must be live (approved) and have creatives assigned to them.
  • The creatives' flight dates must start past the line item start date and end before the line item ends.
  • When troubleshooting, wait 20 minutes after approving the line item to see if the ad unit is still blank. This is because information from DFP pushes to the ad server every 20 minutes.

Line item delivery settings

  • You selected Only one for the “Display creatives” setting, but there are multiple tags to which the line item can be delivered.
  • Existing ads may have hit their daily impression goals, or they may have other targeting (like geo, dayparting, or frequency caps) that prevents them from serving to you.
  • Check any frequency cap or advertiser exclusion labels assigned to the line item to see if they prevent the line item from delivering.

Errors prevent an ad from delivering or rendering

If the previous two scenarios are not applicable, it’s likely that the ad is serving to the page but is not rendering properly. Use Chrome Developer Tools to:

  1. Check the network requests and ensure you’re getting the appropriate HTTP 200 responses for each ad request.
  2. Check the console to see if there are any JavaScript errors that may be leading to creative rendering issues.

Inventory that you want to leave unfilled

For inventory that you want to leave unfilled — for example, in cases of unsold inventory where you'd rather not run a house ad — create a 1x1 pixel blank house ad. The house ad can be delivered so that in reports you can track unfilled impressions separately from intentional blanks.

  1. Create an advertiser for your house ad, if you don't have one already.
  2. Create an order for your 1x1 pixel line items.
  3. Create a new line item for each ad slot size on your website where you want to serve blanks. For these line items:
    1. Set the size to the size of the ad slot, not 1x1.
    2. Set the Type to House.
    3. Set the targeting to Run of network, or to the areas of your website that make the most sense.
  4. Add a 1x1 pixel image creative to the line item, and override the line item's size. You can use any 1x1 pixel image, either hosted in DFP or remotely. The click-through URL is required but isn't used, so you can enter any value.
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