Some e-commerce platforms or online marketplaces (such as e.g. Amazon or Google) might require that the products you sell on their marketplace have a Global Trade Item Number (GTIN), a Manufacturer Part Number (MPN), or other product identifiers.
If you offer Gelato products, you may not be able to provide GTIN, MPN, or brand name for these products. To get around this issue, you’ll want to remove these identifying attributes from your product feed altogether, then include an attribute for "identifier_exists” and apply “FALSE” for all products listed.
In some cases, you might have to request a GTIN exemption from the e-commerce platform or online marketplace.
Please refer to their website, Help Center and Customer Support for additional information - some examples are below: