Invalid MPN value

CAT_VALIDATION_ERROR_MPN_INVALID fires when the manufacturer part number is missing or malformed. MPN is required when brand and gtin are both absent, and must match the value the manufacturer prints on the product packaging.

Snap Catalog Manager uses identifiers (GTIN, MPN, brand, SKU) to match catalog records. Issues come from invalid format (non-numeric in a GTIN field), brand-GTIN mismatches in GS1's database, duplicate IDs across SKUs, or missing required identifiers for the category.

1. Verify GTIN ownership using GS1 GEPIR (https://gepir.gs1.org) — confirms which brand legitimately owns the code.
2. Strip non-numeric characters from GTINs: no dashes, no letters, no spaces.
3. Check ID lengths: UPC = 12 digits, EAN-13 = 13 digits, ISBN-13 = 13 digits starting 978/979.
4. If your product is private-label without a real GTIN, request the channel's GTIN exemption process rather than fabricating one.
5. Re-submit; new identifiers take 24–72 hours to propagate.

• Buying GTINs from non-GS1 resellers — usually maps to defunct brands and triggers validation
• Reusing the same GTIN across multipack and single-unit variants — flagged as duplicate