How to solve the WordPress error ‘There has been a critical error on this website’

The error message ‘There has been a critical error on this website’ causes WordPress websites to stop working. In this article, we show common causes and provide tips to get your website back up and running quickly.

Common causes of the error message include a WordPress update or a newly installed plugin that’s in­com­pat­ible with existing themes and plugins. Re­gard­less of the cause, prompt action is essential to get the affected website up and running again quickly.

What causes the ‘There has been a critical error on this website’ WordPress error message?

Since a variety of issues can cause the error message, start by checking the most common sources of error first. This will help you rule out the most likely problems before in­vest­ig­at­ing less common causes.

The most common causes include:

• In­com­pat­ible themes or plugins: A newly installed or updated theme or plugin often causes issues with the existing con­fig­ur­a­tion. For instance, changes might result in com­pat­ib­il­ity problems with the current WordPress version or with other themes and plugins.
• Faulty WordPress files: Missing or corrupted files in the WordPress core can also be re­spons­ible for a website no longer working and a cor­res­pond­ing error message appearing.
• Server failures or network faults: Sometimes errors can stem from issues beyond your control, such as server dis­rup­tions or network problems. These issues can make the website un­avail­able and display an error message, even if WordPress itself is not at fault.
• Problems with the PHP version: Outdated or un­sup­por­ted PHP versions are common causes of issues on managed websites, leading to in­com­pat­ib­il­it­ies.
• Storage space problems on the server: Ac­cu­mu­lat­ing data can exhaust server storage, po­ten­tially causing certain processes to fail.

In addition to the more well-known causes, there are also rarer factors that can trigger the error message ‘There has been a critical error on this website’ on WordPress:

• Problems within the database: Corrupted tables or missing data can cause conflicts in the WordPress database, leading to the website not loading properly.
• Errors in the server con­fig­ur­a­tion: In­suf­fi­cient resources or incorrect file per­mis­sions are rare but can also trigger the error message.
• Risks due to security incidents: Security issues or cyber-attacks, such as hacking, can cause critical errors, often taking the website offline for an extended period and po­ten­tially causing con­sid­er­able damage.

In some cases, the cause of the error message is im­me­di­ately obvious, while in others, it’s not clear. A thorough manual diagnosis is essential for un­der­stand­ing the situation and identi­fy­ing the cause. Conduct the diagnosis step by step by isolating in­di­vidu­al com­pon­ents of the website to sys­tem­at­ic­ally eliminate potential sources of error. Once you’ve iden­ti­fied the issue, proceed to rectify it.

How do you fix the WordPress error message ‘There has been a critical error on this website’?

To resolve the error message and get to the bottom of potential causes, activate WordPress debugging or run a WordPress Debug. To do this, enter the following code in wp-config.php:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);
@ini_set('display_errors', 0);

Af­ter­wards, check the wp-content/debug.log file for error messages.

Other possible solutions include:

• De­ac­tiv­ate all plugins: To rule out faulty plugins as a cause, de­ac­tiv­ate them all. You can do this by renaming the plugins folder via FTP to something like plugins_deactivated, for example. If this resolves the issue or elim­in­ates plugins as the cause, rename the folder back to its original name. Al­tern­at­ively, if you have access to the WordPress backend, you can de­ac­tiv­ate all plugins from the Plugins section.
• Clear the cache: Outdated or stored data, such as cached page content, can cause issues. Clearing the cache in WordPress can often resolve the error and make WordPress faster. To clear the WordPress cache, go to ‘Settings’ in the backend, select ‘Cache’, and confirm the cleanup. If the backend is in­ac­cess­ible, you can clear the cache using other methods, such as:

cd wp-content/cache
rm -rf *

• Switch to the default theme: If a faulty theme is causing the error, switching to a default theme like Twenty Twenty can help resolve the issue. If you have access to the backend, go to the ‘Design’ section and activate a default theme. If the backend is in­ac­cess­ible, use FTP to navigate to wp-content/themes, rename or delete the current theme folder, and upload a default theme, or use a backup if available.
• Check file per­mis­sions: Incorrect file per­mis­sions can also lead to problems. Check the per­mis­sions for the wp-content, wp-includes and wp-admin dir­ect­or­ies. These should be set to default values such as 755 or 750, for files the values 644 or 640 apply.
• Restore backup: If previous attempts to fix the problem fail, restoring from a backup is often necessary. This will revert all data to the state of the last backup. Regularly creating WordPress backups is crucial for pre­par­a­tion in emer­gen­cies.
• Increase PHP memory limit: In some cases, it is enough to simply increase the allocated memory. To do this, add the following code to the wp-config.php file: define('WP_MEMORY_LIMIT', '256M');
• Check or update PHP version: An outdated or in­com­pat­ible PHP version can cause a website to fail. Typically, you’ll need to contact your hosting provider. Al­tern­at­ively, you may be able to change the PHP version through the hosting control panel.