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

The message means PHP stopped with a fatal error, and WordPress hid the details from visitors. The cause is usually a plugin, a theme or custom code, often right after an update. Work through it in this order:

1. Open the recovery mode email WordPress sent to the admin address. It names the plugin or theme that failed.
2. No email? Turn on the debug log and read the last fatal error in wp-content/debug.log.
3. Deactivate the plugin, or switch away from the theme, that the email or the log names.
4. Still unclear? Turn all plugins off, then back on one at a time.
5. Check the PHP version and the memory limit.
6. Restore a backup, reinstall WordPress core, or ask your host for the server error log.

Since WordPress 5.2, a fatal error no longer leaves a blank page. Before that, a broken plugin usually caused the “white screen of death”. Now WordPress catches the error and visitors see There has been a critical error on this website. In wp-admin and on the login page the message adds Please check your site admin email inbox for instructions.

At the same time WordPress turns on recovery mode. It does this for fatal PHP errors during a normal page load, not for errors in scheduled tasks. The usual causes:

• A plugin or theme update that conflicts with another plugin, or with your PHP version.
• A mistake in custom code, such as a snippet pasted into functions.php.
• PHP running out of memory on a heavy page.
• An update that stopped halfway, or damaged files.

Look for an email from your site with the subject Your Site is Experiencing a Technical Issue. It names the plugin or theme that caused the error, quotes the error, and contains a link that logs you in with that plugin or theme paused. The link is valid for one day.

1. Open the link and log in.
2. Read the notice at the top of the dashboard: it points to the plugin or theme that failed.
3. Deactivate that plugin under Plugins, or switch themes under Appearance > Themes.
4. Click Exit Recovery Mode in the toolbar, then load the site as a visitor.

The pause only covers your session, so visitors keep seeing the error until you deactivate or fix the plugin. The email often lands in spam or never arrives: the error can stop WordPress before an email plugin loads, so the message goes straight from the server.

The debug log records the exact error, including the file it came from. Open wp-config.php over SFTP or your host’s file manager and add these lines above the line that says That’s all, stop editing!:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

Reload the page that shows the error, then open wp-content/debug.log. The last line that starts with PHP Fatal error names the culprit: a path under wp-content/plugins/ points to that plugin’s folder, and one under wp-content/themes/ to the theme.

The WordPress handbook warns that debug mode is meant for testing, not live sites, and on most hosts anyone who knows the address can open debug.log. Set WP_DEBUG back to false and delete the log as soon as you have the error.

If you can reach wp-admin through recovery mode, deactivate it there. If you can’t, there are two other ways:

• Rename its folder. In wp-content/plugins, add -off to the plugin’s folder name. WordPress can’t find the plugin, so it deactivates it. Rename the folder back later and reactivate the plugin once it’s fixed. For a theme, rename its folder in wp-content/themes; WordPress falls back to a default theme such as Twenty Twenty-Five if one is installed.
• Use WP-CLI. The skip flags load WordPress without the broken code, so the command still runs:

wp plugin deactivate plugin-slug --skip-plugins --skip-themes

When the log doesn’t point to one plugin, switch them all off and bring them back one by one. Deactivate every plugin from the Plugins screen, rename the whole plugins folder, or run:

wp plugin deactivate --all --skip-plugins --skip-themes

If the site loads, reactivate plugins one at a time and reload after each. The one that brings the error back is the cause. With every plugin off, features such as checkout and forms stop working too, so test at a quiet time or on a staging copy.

An error that says Allowed memory size of … bytes exhausted means PHP ran out of memory. Raise WordPress’s limit in wp-config.php; your host’s own PHP limit can still cap it:

define( 'WP_MEMORY_LIMIT', '256M' );

If the error started when your host changed PHP versions, a plugin or theme may not support the new one. Update it, or switch PHP back in your hosting panel until the developer ships a fix. WordPress recommends PHP 8.3 or newer.

If a recent change broke the site and you can’t find which one, restore the last good backup from your host or your backup plugin. Content added since that backup is lost, so export anything new first if you can.

If WordPress’s own files are damaged, WP-CLI can check them against the official copies and re-download core without touching wp-content. Dashboard > Updates also has a button to re-install the current version:

wp core verify-checksums
wp core download --force --skip-content

Still stuck? Ask your host for the PHP error log from the server. Many show it in the control panel, and it records errors that happen before WordPress can write its own log.

• Update plugins one at a time, or on a staging copy first, and check your key pages after each.
• Keep automatic off-site backups, and test a restore now and then.
• Put custom code in a child theme or a must-use plugin, never in a parent theme’s files.
• Keep PHP current, and check a plugin’s support before your host moves you to a new PHP version.
• Follow our WordPress security checklist, since the same upkeep prevents both.

WPOS can’t repair a site that won’t load. Its agent works inside wp-admin, so when every page shows the critical error, start with recovery mode or the steps above. Where it helps is the routine that prevents the next one: the agent checks its own render with a browser screenshot before it reports a change as done, and the free trial comes with a staging sandbox next to the live site for trying updates first. A check after updates becomes one request:

“Open the home, pricing and contact pages and every page in the main menu, take a screenshot of each, and list any that show an error.”

WPOS is our product, so weigh this section accordingly; you can try it free for 30 days with 5,000 credits, a live site plus a staging sandbox, and no card.