"Error: Shipping policy is required."

In order to list on eBay, you will need to set up your eBay business policies, which include a Shipping, Return, and Payment policy. Here is a link to opt in to the business policies; http://www.bizpolicy.ebay.com/businesspolicy/policyoptin 

Once you have set up your Shipping Policy, you will need to set the polices for the products. Here are the steps to adding a Shipping Policy to all products that do not have one assigned: 

1. Navigate to Settings > Listing Settings > Listing Defaults
2. Click on the eBay logo (if you have multiple eBay storefronts, hover over the icon to see the name you have assigned that storefront).
3. Scroll to the bottom of the page and choose a Shipping Policy from the Shipping Policy drop down menu
   
4. Click "Save"

Now you can then list the product(s) to your eBay storefront. 

**Remember, you can also upload the policy ID's in bulk through a .csv file upload**