Error Code 5995?

I’m trying to sell a few used books on Amazon, and my application has been approved for all of the brands, but they are still showing up as unable to be added. When I reached out to Amazon CS about this, they said that I needed to include the word ‘branded’ at the end of the Brand name on vital info, but when I try to do that I am getting an error (code 5995).

Has anyone else experienced this? Seller CS is completely useless in this and keeps telling me to register my brand.