Amazon has special (not well taught/explained) rules regarding use of a Brand's name or if you are a Brand-Registered Company within amazon's special brand program.
Below are two examples an error message with a corresponding solution for using your barcode properly according to amazon's rules.
1: Brand Name Error
It means you're attempting to use a bar code with a branded item that is not licensed by that brand, ie: that brand (ex: Nike) has their own bar code numbers and they are different then the one you're attempting to use with the branded product.
The solution or "work-around" is to not use that company's manufacturer name or brand name. Their automated system is cross-referencing your barcode number (the one you bought & own) to that companies own bar code #'s and they know it doesn't match, nor should it. So instead you would use your own company name and THEN put the brand/manufacturer name in the item description field.
2: Brand-Registered Seller Program Requirements
This is a very similar error message as #1. Amazon does not provide very understandable or explanatory messages for their error codes, but we have learned what they mean through many years of seller support.
As of the beginning of 2018 (around march) we found out that amazon had changed their rules for brands and are now forcing all of these brands to rent their GTIN's from GS1 directly. This means that while your existing owned-GTIN's are still fine and work in almost every POS system on earth, for this special program you do not have a choice and are made to borrow them on an annual basis from GS1 for a hefty fee.
If you see this error message as a brand-registered seller/company this means you are attempting to use a GTIN that does not match what GS1 has on file for your company name. Amazon has a non-public (also non-searchable) database of all companies that they have inducted into (or that you applied to get into) their special brand-registered seller program, this short list of companies/names is always referenced & compared to GS1's current barcode rental information provided by GS1 on their public GEPIR database here: http://gepir.gs1.org/index.php/search-by-gtin
There is no solution for this, as the entire purpose for this change is to have a single database so amazon can control their sellers/listings and "customer experience". The legalities of this move by amazon are not settled, on one hand they can make these rules as a private company, on the other hand they are trying to prevent you from using what you legally own and is factually a proper GTIN from GS1-USA that you own the rights to.