If you're using Preorder Pro + Back in Stock and customers are seeing an empty cart after adding a preorder item, check thatContinue selling when out of stock is enabled.
Here’s how:
- In your Shopify admin, go to the product page.
- ClickEdit on the variant you want to update.
- In theInventory section, check the box forContinue selling when out of stock.
- ClickSave.
After updating, it may take a few minutes for the change to take effect. Ask your customer to refresh the page or clear their cart before trying again.
Originally from our Help Center