I have tried re-installing your X theme and Cornerstone plugins, but I still see that you're getting the cURL error (https://wordpress.org/support/topic-tag/curl-error-7/).
To populate this demo area, also needs cURL extension to work properly. Please contact your hosting provider and make sure that your firewall is not blocking any requests to theme.co.
In case if you require further troubleshooting on our end, please include your FTP credentials as well in your secure note.
Let us know how it goes.