Last week, your company launched a Programmatic Guaranteed deal in Display & Video 360 for a specialty foods business. You notice while reviewing impressions that the deal under-delivered. What's the first step to figuring out what happened?

The Deal Troubleshooter in Display & Video 360 is specifically designed to diagnose issues with Programmatic Guaranteed deals, making it the most efficient first step. It provides insights into potential problems like bid rejections, targeting conflicts, and discrepancies, which are common causes of under-delivery. While checking for multiple targeting assignments on the line item or reviewing campaign-level targeting could be subsequent steps if the troubleshooter doesn't pinpoint the issue, they are less direct for a Programmatic Guaranteed deal. Contacting the publisher is generally a later step, after internal investigation has been completed and potential issues identified.