Fatal error Cannot declare class Cornerstone_Plugin_Base

Hi there,
My website is out https://leeruniek.nl/. I checked with my host and they told me it’s because of the theme.
I tried deactivating plugins. When activating cornerstone i get this error:

Fatal error : Cannot declare class Cornerstone_Plugin_Base, because the name is already in use in /srv/htdocs/wp-content/plugins/cornerstone/includes/utility/plugin-base.php on line 6

How can i fix this?

The problem is getting bigger and bigger. The only thing i’m seeing now is: There has been a critical error on this website.

Hello Bianca,

Thanks for writing to us.

I am not able to see any error on the frontend. I checked your given credentials but due to your login security plugin, I was not able to access your site dashboard.

It might be the issue of plugin conflict or version compatibility issue. I would suggest you troubleshoot with a few of the common issues before we investigate your settings.

  1. Testing for Plugin Conflict
  2. CSS/JS Customization
  3. Version Compatibility
  4. Disabling Cache
  5. Child Theme

If none of those work, please share your details in a secure note. Please provide the following details. It would be best if you please copy your live site to a staging server so we could troubleshoot freely without breaking your live site.

  • WordPress Login URL (staging server)
  • Admin level username and password (staging server)
  • Exact page URL (staging server)
  • FTP details (staging server)

You can find the Secure Note button at the bottom of your posts


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