Required item specific MPN is missing

Error 21919303 also fires when MPN (Manufacturer Part Number) is a required item-specific for the category and is missing from the listing. The listing is blocked until MPN is populated.

Many categories require MPN to disambiguate products that share a brand. Feeds frequently include only SKU or GTIN and omit MPN entirely. For products that genuinely have no MPN (handmade, custom), you must explicitly submit 'Does Not Apply'.

1. Identify categories where eBay marks MPN as required.
2. Map MPN from your PIM. If the supplier provides it, use the supplier's MPN, not your internal SKU.
3. For products without an MPN, submit exactly 'Does Not Apply' rather than leaving it blank.
4. Confirm MPN, GTIN, and SKU are stored in their own columns - don't conflate them.
5. Resubmit and confirm the listing publishes.

• Submitting your internal SKU as the MPN
• Leaving MPN blank in handmade categories - eBay needs 'Does Not Apply'
• Re-using the same MPN across multiple variants