Hey Andi,
The Legacy X Integration option was introduced in X 6.3 and Cornerstone 3.3. Please read our previous Release Note here: https://theme.co/apex/forum/t/release-notes-pro-2-3-x-6-3-cornerstone-3-3/44607
I checked your site and you’re using a very old version of X, Cornerstone and Visual Composer. The issue in your site could be a result of version incompatibility. It’s hard to track them as the software version of the products you’re using is very old so please update to the latest versions first. You can see the latest version of X, Cornerstone and the bundled plugins here: https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195. I’d like to add that the latest version always go with the latest WordPress version. If you’ve updated WordPress and still use old theme and plugin versions, it could break your site. The reverse is the same. If you’ve updated themes and plugins but not WordPress, it could also break your site.
Only update your Visual Composer created content after you have completed the updates. Otherwise, you’ll get the issue like in this video:
https://youtu.be/ur6pO1YrykQ
It’s fixable but it’s tricky. There’s no automated way to fix that.
If the issue persists after updating everything and the issue is also not like in the video, please give us WordPress Admin and FTP access in a Secure Note
Thanks.