We have been working hard to find a solution on how to provide full visibility on why Amazon listings are not active.

Previously we were not able to retrieve the error when your listing were under Complete your listings within Seller Center - https://sellercentral.amazon.com.au/fixyourproducts/drafts i.e. as below:

Amazon have recently released an update to their APIs that now allows us to retrieve these errors.

We now are able to show these errors via our Product Diagnostics section, which will provide you with full visibility within Marketplace Maximizer without you having to login to Seller Center.