Dynamic ads with zero sales for $8K — the product IDs never matched the catalog

The situation

A luxury watch retailer in Dubai had built a beautiful Meta product catalog with 340 watch SKUs. They launched Dynamic Product Ads (DPA) targeting website visitors who had viewed watches. After 3 weeks and $8K spent, DPA reported zero purchase conversions despite the brand's website showing normal sales volume.

The problem

The Meta pixel was sending ViewContent and AddToCart events with product IDs from the website's internal SKU system (e.g., "ROLEX-116610LN"). The Meta product catalog had been created using the Shopify product ID format (e.g., "7823456789"). Meta DPA matches pixel event product IDs against catalog product IDs to show relevant products — when they don't match, Meta can't connect viewer to product and the DPA system stops working.

What we did

1. Compared pixel ViewContent event product_id values (internal SKU format) against catalog item IDs (Shopify numeric ID) — complete mismatch
2. Two options: update pixel to send Shopify numeric IDs OR update catalog feed to use internal SKU format
3. Chose to update the Shopify catalog feed to use the same SKU format as the website's internal IDs (more stable, doesn't change on variant creation)
4. Regenerated catalog, resubmitted feed, waited 24 hours for catalog re-indexing
5. Re-launched DPA campaigns — purchase events immediately matching to catalog products

Why it worked

Meta DPA is entirely dependent on product ID matching — the pixel event product_id must exactly match the catalog item_id. Brands with complex SKU systems, multiple ID formats, or catalog feeds generated separately from the pixel implementation almost always have this mismatch. It produces the baffling result of DPA campaigns spending freely with zero attributed purchases.