Sometimes when you first set up your Facebook Catalog and start DPA retargeting ads with it, they can be kind of slow to get impressions.
You can check if the pixel events are getting into the catalog and if they match the products. Here is how...
Go to the Trackify Catalog & Feeds entry in the Facebook Tools menu, and click on the Event Sources button:
2. In the event sources you should see a green check mark under Diagnostics. Click on "See All Website Conversions" to inspect all event details:
3. At that point you can inspect the detailed event stats for ViewContent, AddToCart and Purchase events, and any error messages that you may find: