New Seller Problem

I purchased an item (Supplement/Nutritient) in order to sell. I submitted a ton of evidence, an invoice from supplier, and it denied. Now I know it was for the brand because it is a fat burner. My friend who also does business for 4 years took the stranded inventory in my warehouse under his control, and he shipped it and now got notification from Amazon that “the listing is at the risk of deactivation due to missing mandatory compliance requirements for the products.” Any idea what that means or what Amazon is looking for? How can we prove or with what can we prove it, and that doesn’t affect the health of his account?