The campaign validates, is active, but receives too few impressions or don't bid at all on certain inventory.
Start out by getting an overview of what's happening in the life of the campaign, the campaign log (Campaigns -> Overview -> Logs) gives a good view on all things that have changed in the campaign setup-wise, especially interesting is of course events that in time correlates with when eventual delivery problems in the campaign started.
The bid metrics-section (Campaigns -> Overview -> Bid metrics) provides insights into primarily the reasons why bids haven't been placed for the campaign.
Bid or no bid
The next step is to figure out if the campaign isn't placing bids at all or don't place enough bids/win enough impression for placed bids. Look into the bid metrics-section and look for "Internal auctions won / Bids submitted", select a bid strategy in the drop down if you're troubleshooting a specific bid strategy.
If the campaign have placed a "reasonable amount" of bids in relationship to its targets, reach out to the SSP in question and see why the campaign doesn't win impressions.
Not enough bids
- If the campaign is running on a limited selection of sites, consider widening the selection.
- Is the deal active?
- Do we receive deal requests on the creative formats used by campaign?
- Do deal request volumes match what have been said by the publisher?
- Make sure we don't bid below the floor price when audience and Bidtheatre costs have been subtracted from the max bid CPM.
- Is deal and sites correctly linked to the sitelist used.
- Do campaign creatives have appropriate formats in relation to the targeted sites?
- Are creatives audited?
- Are creatives HTTPS compatible (and marked as such)?
- Is the audience population large enough?
- Is the content of the audience resonable and setup correctly?
- Is the cost of the audience to high in relation to the max CPM ?
- Take a minute and make sure you understand what the different targeting options do, most will limit available supply.
- Use "Frequency Cap Min" only for selected strategies and in combination with strategies without "Frequency Cap Min" set.
- Modify frequency cap settings, increase "Frequency Cap Max" and/or decrease "Frequency Cap Timeout (hours)"
- Consider not using "Above the fold" targeting.
- Is the targeted geo region reasonable and large enough or could it be made larger?
Low win rate
A low win rate can indicate that the bid CPM is to low or that the campaign is blocked by the SSP, try increasing the max bid CPM and/or reach out to the SSP to get details into why bids aren't won.
If it seem to be a problem with a specific, large, site or sites (Campaigns -> Sites), try applying the above troubleshooting guide to the individual site.