Amazon regularly blocks asin's with nonsense reason - BAD GTIN/EAN:

This ASIN has GTIN codes that do not match the brand associated to the ASIN. GTIN codes are reliable data that are used to limit duplicate products in the catalogue and ensure product authenticity. We verify the authenticity of GTINs by checking the GS1 database and GTINs that do not match information in GS1 are considered invalid. We recommend obtaining your GTINs directly from GS1 (and not from other third parties selling GTIN licences) to ensure the appropriate information is reflected in the GS1 database. If you believe we have removed your ASIN in error, contact Selling Partner Support here. Repeatedly creating ASINs for brands you do not have a relationship with will result in the removal of ASIN creation abilities.

This is complete nonsense because:

1) when seller uses ADD A PRODUCT option he has no option to change GTIN/EAN,

Seller doesn't have any chance to stay safe even if ean code on his boxes is good,

seller takes penalty for asin creator who didn't use GTIN good for Amazon

2) Amazon blocks asin and forces seller to use GS1 site where registration is PAID and seller MUST BUY

new EAN from GS1,

This is complete robbery, Amazon and GS1 just steal money from sellers