Sales channel apps such as Meta and Google identify each product or variant on their platform by a product ID. The ID comes from the source chosen in the app's settings, such as the SKU or a metafield.
A product or variant whose ID is missing, longer than 255 characters, or the same as another product's can't be sent. It is left out of the app's catalog feed and of the product details in ad events. Orders are still reported; only that product is missing from them.
Find the products
Open the app from Apps. For Meta, go to Settings > Meta IDs; for Google, go to Channel identities. An ID with problems shows Needs attention and how many products are missing an ID or have a conflict.
Choose Review to list them. Search by product name or SKU, or filter by the problem, and choose Load more to see further products. In Store Admin and in the Tringify app, Edit product opens the product.
Fix them
No value: fill in the source the app uses, such as the product's SKU or the metafield chosen in the app's settings.
Same value as another product: give each product or variant its own value.
Longer than 255 characters: shorten the value.
Reopen the list to check it is empty. The app picks up the new values the next time it sends the product.