An advertiser sets up a conversion campaign with three ad groups. Each group targets customers who previously added items to their cart, using keywords and customer mailing lists to do so. After the campaign has been “live” for two months, the advertiser notices the campaign is under-delivering. The advertiser checks each ad group's performance and sees that the targeting customer mailing lists did not spend in the last five days. What should the advertiser do first to help the mailing list ad group deliver?

The first step should be to check for an audience issue because the mailing list ad group stopped spending. This indicates a potential problem with the audience size or validity. The mailing list might be too small, outdated, or have a low match rate on Pinterest, preventing ads from being delivered. Creating a new ad group with interest targeting is a viable next step if the mailing list is indeed the problem, but it's not the first action. Pausing the campaign and creating a new one under a new objective is a drastic measure and unnecessary without first diagnosing the current issue. Adding new carousel Pins is a creative optimization tactic, but it won't resolve an underlying audience delivery problem.