Reasons why a line item may not be being delivered

The line items listed in the debug diagnostics screen either target the ad unit, the ad unit’s parent, the placements in which the ad unit is contained or the placements in which the ad unit’s parent is contained, and are being served today. If an ad unit or a placement is explicitly targeted, then the debug diagnostics screen only shows line items targeted to that ad unit or placement; line items targeted to ad units in a level above the explicitly targeted ad unit or placement will not be listed.

 
Reason why the line item isn't being delivered Description How to get your line item delivered
Ahead of schedule Delivery for these line items has slowed to ensure that they aren't overdelivered. Ensure that the flight dates, quantity goals and frequency caps are correct.
Current time outside day-parting window These line items were targeted to times of day different from the ones targeted by the ad unit. Ensure that the day-parting settings are correct.
Delivery goals reached These line items have stopped being served because they have reached their quantity goals or their end date has passed. If you need to restart the line item, you must copy it and give it new start and end dates.
Frequency cap reached These line items have hit the limit for how many times they can be delivered to the same user within the established time period. Ensure that the frequency capping settings are correct.
Incompatible start or end date The flight dates of these line items don’t match the targeting settings of the ad unit. Ensure that the flight dates of the line item that you want to deliver match the flight dates of the ad unit.
Limited by number of ads per page There aren't enough ad slots on the page to accommodate all of the creatives that the line items are set to deliver. Ensure that the number of creatives is equal to or less than the number of ad slots on the page.
Line item not active The line items haven't started running, either because their flight dates and times haven't started yet or the line items haven't been activated. See Line item isn't delivering ads to troubleshoot the problem.
Line item not ready The line items need creatives, have been paused or cancelled, or their inventory was released. Add creatives, check why they were paused or cancelled, or check why their inventory was released.
No active correctly sized creative associated The line items don't have creatives that match the sizes of the ad slots on the page. Add at least one creative that has the same size as an ad unit on the page.
Not targeting any active ad units The line items aren't targeting any of the ad units on the page. Check the line item's inventory targeting and ensure that it's targeting at least one of the ad units on the page.
Not targeting any active placements The line items aren't targeting any placements assigned to this web page. Check the line item's inventory targeting and ensure that it's targeting at least one of the placements assigned to this web page.
Order not approved The order that contains the line items must be approved before the ad can be delivered. Ensure that the order is eligible for approval.
Preempted by another ad of higher priority These line items conflict with another line item that has higher priority. Ensure that the priority is set correctly. You can change the priority by selecting a different line item type or adjusting your targeting criteria.
Preempted by another same-priority ad that was behind schedule If a line item falls behind, Google DFP may deliver up to 120% of the daily goal until the line item is back on track. The line item that's behind schedule may displace other line items. Ensure that line item settings are correct.
Priority ranked lower The line items have a lower delivery priority than the winning line item. Ensure that priorities of line items are correct. You can change priorities by selecting different line item types.
Road-blocking rules prevented delivery Creatives won't repeat on a single web page. Creatives for a line item will be served in as many ad units on the page as the line item is eligible for. Ensure that road-blocking rules are set correctly.
Unmatched targeting or unknown The line items aren't targeting the same options as the ad unit. If you want a different line item delivered to the ad unit, ensure that the targeting matches that of the ad unit.
Unknown reason Your line item was rejected for a reason other than the ones listed above. Try running the diagnostic tool again. Google DFP will take note of what has happened, so that we can investigate.