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How to Fix "There Has Been a Critical Error on This Website" in WordPress

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When a WordPress site displays the message "There has been a critical error on this website. Learn more about troubleshooting WordPress," it indicates a PHP fatal error occurred on your server. This is typically caused by a plugin bug, a software version mismatch, or an outdated PHP environment.
 
This guide shows you how to locate the exact cause using Plesk tools and how to resolve common real-world scenarios.
 
Step 1: Enable Debugging in Plesk
 
By default, WordPress hides specific technical details from public visitors. You can easily reveal the underlying error message directly from your hosting dashboard:
  1. Log into your Plesk Control Panel.
  2. Select WordPress from the left-hand navigation menu.
  3. Under the Tools section, locate Debugging and toggle the switch to On.
  4. Refresh your website in a web browser to view the generated error on your screen.
Step 2: Check Your Server Error Logs
To view full error details and stack traces inside Plesk:
  1. Inside your Plesk Control Panel, click on Logs (or Dashboard > Logs).
  2. Filter or scroll through the real-time log entries to locate recent PHP Fatal error entries.
Step 3: Identify the Error Type & Apply the Fix
Below are three real-world log examples generated by WordPress fatal errors, along with instructions on how to diagnose and resolve them:
 

Scenario A: Single Broken Plugin (e.g., Caching or Utility Plugins)

Real Log Output:
2026-08-28 13:53:10 Error 72.138.80.242 AH01071: Got error 'PHP message: PHP Fatal error: Uncaught TypeError: substr(): Argument #1 ($string) must be of type string, int given in /data/vhosts/example.com/httpdocs/wp-content/plugins/wp-rocket/inc/ThirdParty/Plugins/CDN/Cloudflare.php:562
Stack trace:
#0 /data/vhosts/example.com/httpdocs/wp-content/plugins/wp-rocket/inc/ThirdParty/Plugins/CDN/Cloudflare.php(562): substr()
#1 /data/vhosts/example.com/httpdocs/wp-content/plugins/wp-rocket/inc/ThirdParty/Plugins/CDN/Cloudflare.php(535): WP_Rocket\ThirdParty\Plugins\CDN\Cloudflare->unregister_callback()
#2 /data/vhosts/example.com/httpdocs/wp-includes/class-wp-hook.php(353): WP_Rocket\ThirdParty\Plugins\CDN\Cloudflare->unregister_cloudflare_clean_on_post()
...
thrown in /data/vhosts/example.com/httpdocs/wp-content/plugins/wp-rocket/inc/ThirdParty/Plugins/CDN/Cloudflare.php on line 562', referer: https://canada14.rebel.com:8443/
  • Cause: A specific plugin encountered a bug following a system or core update. Looking at the file path inside the stack trace (/wp-content/plugins/wp-rocket/...), we can confirm the caching plugin triggered the error.
     
  • Fix:
    1. Open Plesk File Manager and go to /wp-content/plugins/.
       
    2. Locate the broken plugin folder (e.g., wp-rocket) and rename it by adding _OFF (e.g., wp-rocket_OFF).
       
    3. Refresh your website to confirm access is restored.
       
    4. Log into /wp-admin, update the plugin to the latest version, and remove _OFF from the folder name to reactivate it.

Scenario B: Version Mismatch (e.g., Core Elementor vs. Elementor Pro)

Real Log Output:
2026-08-28 13:55:58 Error 134.195.196.134 AH01071: Got error 'PHP message: PHP Fatal error: Access level to ElementorPro\Modules\ThemeBuilder\Documents\Theme_Document::get_create_url() must be public (as in class Elementor\Core\Base\Document) in /data/vhosts/example.com/httpdocs/wp-content/plugins/elementor-pro/modules/theme-builder/documents/theme-document.php on line 123', referer: https://canada14.rebel.com:8443/
  • Cause: A free base plugin (like core Elementor) was updated, but its premium add-on (Elementor Pro) remains on an older version, creating a code incompatibility where class access rules no longer match (public vs. protected).
     
  • Fix:
    1. Access your WordPress Admin (/wp-admin) or File Manager.
    2. If the dashboard is accessible, navigate to Plugins > Installed Plugins and update the premium add-on (Elementor Pro) to match the core plugin version.
    3. If automatic updates are unavailable, download the latest .zip package directly from your vendor account (e.g., Elementor.com) and upload/overwrite the plugin folder in File Manager.

Scenario C: PHP Version Conflict & Syntax Errors

Real Log Output:
2026-08-28 13:53:10 Error 72.138.80.242 AH01071: Got error 'PHP message: PHP Parse error: syntax error, unexpected 'string' (T_STRING), expecting function (T_FUNCTION) or const (T_CONST) in /data/vhosts/example.com/httpdocs/wp-content/plugins/header-footer-elementor/inc/class-hfe-update.php on line 32'
2026-08-28 13:59:01 Warning 72.138.80.242 AH01071: Got error 'PHP message: PHP Deprecated: Creation of dynamic property PowerpackElementsLite\Classes\PP_Elements_WPML::$type is deprecated in /data/vhosts/example.com/httpdocs/wp-content/plugins/powerpack-lite-for-elementor/classes/class-pp-wpml.php on line 8'
  • Cause: The domain is running a newer PHP version (e.g., PHP 8.2 or 8.3) than your active theme or plugins support, leading to PHP Parse error or PHP Deprecated notices.
     
  • Fix:
    1. In Plesk > PHP Settings for your domain, temporarily lower the PHP handler (e.g., from PHP 8.2/8.3 down to PHP 8.1).
    2. Refresh your site to restore functionality.
    3. Update all installed themes and add-on plugins before upgrading PHP again.
Step 4: Clean Up & Disable Debugging
  1. Once the site is functioning properly and all software is updated, go back to Plesk > WordPress > Tools.
  2. Toggle Debugging back to Off so technical error messages are hidden from public view.

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