I keep getting this message when i open the cornerstone editor and i don’t know what to do
here is the link to the website: http://experience2017.nl/experience2017.nl/
Pleas help!! 
Hello There,
Thanks for writing in! Can you confirm that you are fully updated? (Theme and Plugins)
Our latest versions are:
X Theme: 5.1.1
Cornerstone: 2.0.6
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 If you find anything to be out of date, you can review our update guide.
Or this could be caused by a 3rd party plugin. You could try testing 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.
If the issue still exist, please re install X theme and Cornerstone. There might be some files that were corrupted. You can review our update guide and see the Manual Update section to re install X.
Please let us know how it goes.