Amazon's Build International Listings tool is for Amazon Seller Central users.  It is designed to help users who are managing Amazon directly on Amazon create and update offers from a single source marketplace to one or more target marketplaces.

However, it is not a full sync product and is not compatible with Codisto.  (There should be no need to want to use it because it's easier to link to multiple international Amazon marketplaces using Codisto anyway). Users must Remove the connection using Build International Listings.

The reason Codisto is not compatibile is because the Build International listings tool is not a full sync product so it can't synchronize all that Codisto can synchronize.  The part sync that is performed is also 'hidden' i.e. Codisto can't read what has happened and 'fill in the gaps' to provide full working sync.

If you do use Amazon's tool in conjunction with Codisto you will end up with strange synchronization results and hence, Codisto users must remove the connection using Build International Listings.

Once the connection is removed, Codisto users can easily connect additional international Amazon marketplace sites (in 'Settings') and configure these sites in the tabs in the Marketplace listings view.  Enabled products will be synced across all Marketplaces and your ecommerce platform.