Amazon's Build International Listings tool is for Amazon Seller Central users. It is designed to help users who are managing listings directly on Amazon to target multiple Amazon international marketplaces.
However, this is not a full-sync product and is not compatible with Marketplace Connect
You can already link to multiple international Amazon marketplaces through Marketplace Connect.
Using this tool in conjunction with Marketplace Connect may cause errors with synchronization results. Remove the connection using Build International Listings.
Once the connection is removed, you can easily add additional international Amazon marketplace via the settings tab in the Marketplace Connect app.
For further assistance, please reach out to firstname.lastname@example.org