Amazon error 8008: The item you are creating duplicates an existing ASINAmazon matched your row - usually on UPC/EAN/GTIN, or on brand plus part number - to a product that already exists in the catalog. Creating a second ASIN for the same physical product is not allowed, so the create request is rejected.How to fix error 8008

Search the catalog for your UPC/EAN and for 'brand + MPN' to find the ASIN Amazon matched you to.

Switch from a create feed to an offer-only feed: supply item_sku, external_product_id (or the ASIN), price, quantity and condition, and drop all descriptive columns.

If the matched ASIN is genuinely a different product, gather proof (manufacturer page, packaging photos showing the barcode) and open a Seller Support case to have the match broken.

Do not re-run the same create feed - it will keep failing and can flag the account for duplicate-ASIN abuse.

All Amazon flat-file error codes