The Stock in the product or product’s variations is necessary (cannot be 0). Please provide the stock of your products and variations in the Shopify store and then try to publish the product on Etsy.
To publish the products on Etsy, you must go along with the following steps:
- Visit the "All Products" section under Products
- Select the products that you want to Upload on Etsy by clicking on the checkboxes present on each product's left side
- Then from the "Choose Bulk Action" drop-down select the "Publish on Etsy" option & hit on the ‘Action’ button.
You can also check the link for the video for any help: https://youtu.be/Su0n53BKaTU