Show Notify me button when "Continue selling when out of stock" feature is enabled in your store.

When "Continue selling when out of stock" option is enabled then the sold out button does not appear in sold out product page.

As a result, our “Notify me” button was not appearing previously. However, we have now added an option in the in-app embedded settings. Once you enable this option, the “Notify me” button will appear on these sold-out products.

To enable this setting, please click the “Edit Theme” button.

Enable this option.