Listing a new item not sold on on Amazon

Hi,

It is the first time I have attempted to list a new item not sold on Amazon, I usually sell items that are already listed. I filled out all the information required but then a pop up appeared
5461: You may not create new ASINs for this brand
If you believe that the product you want to sell is not already listed in the Amazon catalogue and should be listed as a new ASIN, [submit an application by clicking here and completing the form]

I clicked on the form but it says I need a letter from the Brand to say I can make listings.

My question is can you list items from any brand that you don’t own but are approved (un gated) to sell or is it just the company that can set up a new page. I thought as an Amazon seller you could do this?