WordPress Automatic plugin can import from various sources including eBay. an API is required and eBay now requires to set an endpoint for Marketplace account deletion/closure so you can make use of the API, here are the steps to set it up

1- once your developer account is created, visit https://developer.ebay.com/my/push?env=production&index=0

then select your APP

2- Visit the plugin settings page and copy the value of the endpoint and the verification token then paste them to eBay page

3- paste the endpoint URL and the verification token then save

Requirements

1- Your site must be in HTTPS and not HTTP as eBay will not accept endpoints URLs from HTTP only sites

2- You will need to set this once for your eBay developer account

3- The endpoint must be always available. If you delete your site, your keys will be disabled