Hi Heike,
Thank you for writing in! Please clear all your site’s caching feature (Plugins, server-side, CDN, and browser’s cache), and see if that resolves the issue. We might also need you to deactivate your caching plugins while we tackle this issue. And whatever you do, do not edit that page outside of Cornerstone.
Ensure you are fully up to date. WordPress, Theme, and Cornerstone.
Version Compatibility
Updating Your Themes and Plugins
If the issue remains, please do a testing for a plugin conflict.
- Disable all plugins except Cornerstone. If you’re using Pro, disable all plugins.
- Test to see if the issue remains.
- If things are working again, reactivate one of your plugins
- Test to see when the problem reappears
- If it does, you know the plugin you most recently activated is causing a problem. If it doesn’t, go reactivate another plugin.
Let us know how it goes,
Cheers!