This listing error simply means that your Etsy shop has not yet been published or is not yet live. Etsy doesn't allow publishing active listings for draft shops.
To resolve this error, follow this guide from Etsy on how to properly set up your Etsy shop. Look out for the final part where you are to click to open your Etsy shop.
Once your Etsy shop has been successfully opened, publish your listing from SynCommerce again to have it successfully listed.
Contact support at email@example.com if the problem persists.