I’m on the X Theme if that helps
I’ve looked at the console in Chrome (control-shift-j) and there is an error message: “Modernizr is not defined” in x-shortcodes.min.js, so you should check all your shortcodes. Maybe temporarily remove them to see if the problem disappears. If so, put them back one at a time to identify the one that is causing the problem.
Check you have the latest version of your theme published only a few days ago on 28 May.
As yours is a commercial theme, the vendor knows the software and is best placed to provide support.