"There has been a critical error on this website": How to Find and Fix It

If your site suddenly shows "There has been a critical error on this website. Please check your site admin email inbox for instructions.", WordPress has caught a fatal PHP error and shut down the frontend (and often wp-admin) to protect itself. This usually happens after a plugin or theme update, or after a PHP version change on the host.

This guide walks through Recovery Mode when the email arrives, and the FTP / wp-config.php path when it does not — the situation most people hit.

What "There has been a critical error on this website" means

Since WordPress 5.2, a fatal PHP error no longer dumps a white screen with no context. Instead, WordPress shows this message and tries to email the site admin a one-time Recovery Mode link so you can log in with plugins temporarily disabled and fix the culprit.

Common triggers:

A plugin or theme update that is incompatible with your PHP version
A jump to PHP 8.x when a plugin still uses deprecated APIs
A conflicting plugin combination after installing something new
Corrupted or incomplete plugin files after a failed update

Fix 1: Use the Recovery Mode email (when it arrives)

Open the inbox for the email address set as the WordPress admin (Settings → General → Administration Email Address).
Find the message from WordPress about a critical error / recovery mode. Check spam if needed.
Click the Recovery Mode link in the email. It logs you into a limited dashboard with the broken plugin or theme flagged.
Deactivate the plugin (or switch the theme) named in the notice.
Reload the front of the site. If it loads, update or replace the offending plugin, or contact its author. Then exit Recovery Mode.

If the email never arrives — which is very common on shared hosts with flaky mail — use Fix 2.

Fix 2: Enable debugging in wp-config.php (no recovery email)

Connect to your site with FTP, SFTP, or your host’s file manager. Open wp-config.php in the WordPress root (the same folder as wp-admin and wp-content).

Find the line that says /* That's all, stop editing! Happy publishing. */ and above it, paste:

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

Save the file. Reload the broken page once so WordPress writes the error, then open:

/wp-content/debug.log

Near the bottom you will see a fatal error pointing to a file path — almost always inside a specific plugin or theme folder. Note that folder name.

Important: Keep WP_DEBUG_DISPLAY set to false on a live site so visitors never see raw PHP errors. Turn debugging off again after you fix the site (set WP_DEBUG back to false or remove the three lines).

Fix 3: Deactivate the culprit via FTP

Once debug.log names the plugin (or you want a fast binary search without the log):

Go to /wp-content/plugins/.
Rename the offending plugin’s folder — for example, bad-plugin → bad-plugin-disabled. WordPress will stop loading it.
Reload your site. If the critical error is gone, you found the cause.
If you do not know which plugin it is, rename the whole plugins folder to plugins_old, confirm the site loads, then restore folders one at a time until the error returns.

For a theme-related fatal error, switch themes by renaming the active theme folder under /wp-content/themes/ so WordPress falls back to a default theme (e.g. Twenty Twenty-Four).

Fix 4: Check PHP version compatibility

Many critical errors appear right after the host upgrades PHP to 8.0, 8.1, 8.2, or 8.3. In your hosting panel:

Confirm which PHP version is active for the site.
Temporarily roll back one minor version if a plugin is not yet compatible.
Update plugins and themes, then move back to a supported PHP version.

WordPress and well-maintained plugins support modern PHP; outdated “set and forget” plugins are the usual holdouts.

Optional: raise memory if the log shows exhaustion

If debug.log mentions Allowed memory size … exhausted instead of a named plugin bug, add this above the “stop editing” line in wp-config.php:

define('WP_MEMORY_LIMIT', '256M');
define('WP_MAX_MEMORY_LIMIT', '512M');

Some managed hosts ignore these constants and require a panel setting or support ticket to change memory_limit. If the lines have no effect, ask your host.

After the site is back

Update or replace the broken plugin/theme, or leave it deactivated if you no longer need it.
Disable debugging in wp-config.php.
Delete or empty wp-content/debug.log if it contains sensitive paths (optional but tidy).
Take a backup before the next bulk update so you can roll back quickly.

Quick checklist

Exact message: There has been a critical error on this website
Try Recovery Mode from the admin email first
If no email: enable WP_DEBUG / WP_DEBUG_LOG, read debug.log
Rename the plugin (or theme) folder via FTP to deactivate it
Confirm PHP version compatibility after host upgrades