Error 6024 or 5665 - You are not authorized to list products under this brand or incomplete listings on Amazon.
Approval request case
In Feeds, you get an error like:

Some products are restricted for sell by Amazon, some are restricted for sell by the manufacturer himself. You should ask for approval prior to list product for this brand.
You should follow the give instruction, then, go to Seller Central and click on Catalogue > Add products;

In the case below, you will have to publish through the wizard (only) one product to be able to list your others;


You don't have to repeat this operation, you will have to make this operation only one time for the whole products of this brand or category.
Once you get the authorization, please go to the App > Catalog > Action and send again your product selection.
Incomplete listings case
In some cases your inventory could look like that:

Click on "Edit" to see the reason:

Selling that kind of products could request an approval. Click on request approval:

Then Amazon will request from you the suitable documents to allow you to sell those products:

Once you will be approved you will be able to list those products from the App.
Worst case
You have been to Catalogue > Add products as detailed above ...
You get the following diagnosis;

In this above case, you won't be able to list the product until you get approval from the brand.
Updated on: 14/01/2025
Thank you!