The problem is that your server blocks cURL requests to our server to download all images https://gyazo.com/8676db19698aacfb5d067b36d391437f
And it breaks all the import functionality. Try to contact your hosting provider for help in this situation.
Example URL that can’t be reached http://dummy.xtemos.com/woodmart/demos/wp-content/uploads/sites/2/2017/06/banner-home-base-2.jpg