Thank you for reaching out to us. I checked your site and I see you're using an old version of X and Cornerstone. The latest versions of X and Cornerstone are 6.3.8 and 3.3.8. Please update X and Cornerstone to the latest version first and see if this resolves the issue. You can find the latest version numbers here: (http://theme.co/changelog/) Then you can compare them to what's installed on your site.
If you find anything to be out of date, you can review our update guide.
If this doesn't help then please check the following:
Clear all caches including browser cache then deactivate your caching plugin and other optimization plugins.
If you're using a CDN, please clear the CDN's cache and disable optimization services.
Test for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it's fixed, you'll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
Let us know how this goes!.