To make the “lock” feature work, you should connect your Amazon Seller Account.

If you have no Amazon Seller Account connected, sign in to your Amazon Seller Central. In In this case, the extension opens a page with restrictions in the background and checks if you can sell the item.

You can connect your Amazon Seller Account in your personal account’s Settings/Integration section or by following the link: https://app.sellerassistant.app/settings#/setup