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

“There has been a critical error on this website” is WordPress being polite about a PHP fatal error: something (almost always a plugin) broke badly enough that the page can’t load, so WordPress hides the ugly details and shows you that line instead. The fastest fix is to make WordPress tell you what actually broke, because the error itself names the culprit. Check the admin email it sent, open recovery mode, or turn on debug logging, then it’s a one-thing fix instead of a guessing game.

We clear this one constantly for agencies whose client site went dark after an update. The order below is the order we actually work in, fastest and most likely first. Back up the site first if you can.

What causes it

A critical error is a PHP fatal error, and on a WordPress site that almost always traces to one of four things:

• A plugin conflict or bad plugin update (by far the most common).
• A theme problem, usually after a theme update or a bad edit to functions.php.
• A PHP version mismatch, where the host upgraded PHP and a plugin hasn’t caught up.
• Exhausted memory.

How to fix it

1. Read the email WordPress already sent you

Since WordPress 5.2, the moment this error fires, WordPress emails your admin address with the subject “Your Site is Experiencing a Technical Issue.” That email usually names the exact plugin or theme that broke, and it includes a recovery mode link that logs you into the admin even though the front end is down. This single step solves most critical errors in about two minutes, so check that inbox first.

2. Make WordPress show you the real error

No email, or it wasn’t specific? Turn on debug logging so the actual PHP error gets written to a file. Open wp-config.php in your site root and find define( 'WP_DEBUG', false );, then replace that line (and add the two below it):

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

Reload the broken page, then read /wp-content/debug.log. The last few lines name the exact file and plugin that threw the fatal error. WordPress documents this in its debugging guide. Set these back to false once you’ve fixed it.

3. Deactivate the plugin that’s breaking it

The error log or the recovery email points at a plugin nine times out of ten. If you can reach the dashboard (or recovery mode), deactivate that plugin. If you’re fully locked out, do it over FTP: rename the /wp-content/plugins/ folder to plugins-off, which deactivates everything at once and gets the site back up, then rename it back and re-enable plugins one at a time until the error returns. That last one is the culprit.

4. Rule out the theme, PHP, and memory

If plugins aren’t it, switch to a default theme (rename the active theme’s folder over FTP and WordPress falls back to a default). Still broken? In your hosting panel, roll PHP back one version (for example 8.3 to 8.2), which fixes the common “host upgraded PHP, a plugin didn’t” case instantly. And if the log mentions “allowed memory size,” raise the limit by adding define( 'WP_MEMORY_LIMIT', '256M' ); to wp-config.

This is the modern White Screen of Death

If you remember the old blank-white-page version of this, you’re not wrong. Before WordPress 5.2, a fatal error gave you nothing at all, the dreaded white screen of death. The critical-error message is the friendlier successor: same underlying PHP fatal error, but now WordPress emails you and gives you recovery mode instead of leaving you staring at a void. The diagnosis is the same skill, and it sits alongside the other common WordPress problems worth knowing cold, like the database connection error and the 500 internal server error.

When to stop and get help

If the log points at something deep, a core file, a host-level limit, or an error that returns the moment you re-enable a plugin you can’t live without, that’s not a moment to experiment on a live client site. This is one of the errors our white-label WordPress team clears quietly under your brand, so your client sees a working site and never knows there was a fire.

Frequently asked questions

If the critical error keeps coming back no matter what you try, it usually means the real cause is buried deeper than the recovery email suggests. Send us the site and a senior developer will diagnose it properly and give you a fixed quote to fix it for good.

Client site throwing this right now and you need it back fast? You can send us the details and we’ll get it online under your brand.