What if I can't find my cart in the list of supported carts.
Shopify users can sell online using different sales channels. Thus, if you have a few of them, it is possible to hide products from the active ones by changing the availability settings.
The migration procedure requires access to the storefront. But once you tick the Allow this app to access data from your storefront checkbox, Shopify automatedly defines the app as a separate sales channel. Consequently, the system hides all the store’s products from it. This doesn’t affect your Shopify migration in any way. To solve the problem, you simply need to uncheck the abovementioned box.