Nexternal recommends searching for the product on http://www.findbrowsenodes.com and using the ASIN returned for one of the matching products. If the product is new to Amazon or the product is not validating, Amazon may not have the UPC in the their database yet. To fix this, try one of the following:
- Apply to enroll the product in the Amazon Brand Registry (see https://sellercentral.amazon.com/gp/help/200955930)
- Submit a UPC exemption request (see https://sellercentral.amazon.com/gp/help/200426310)
- Or if you do not yet have a UPC you can purchase one online. Nexternal recommends using http://shop.nationwidebarcode.com.
If the above does not work, please contact Seller Central Support (https://sellercentral.amazon.com/gp/contact-us/contact-amazon-form.html) for further assistance on getting a UPC that Amazon will recognize.