Fix common WordPress errors

When WordPress fails, the message on screen is only a hint. The real cause, usually a plugin, a theme, the database settings or a PHP limit, is written in a log. This guide shows how to read it and fix the most common errors.

Before you start

• Open the site's files with your panel's File Manager or over SFTP; see upload website files.
• The WordPress root folder holds wp-config.php, wp-admin, wp-content and wp-includes.
• Download a copy of any file before you edit it.

Step 1: Turn on the debug log

Open wp-config.php and add these lines above the line /* That's all, stop editing! Happy publishing. */. If WP_DEBUG is already defined, change that line instead of adding a second one.

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

Reload the broken page, then open wp-content/debug.log. The newest lines are at the end. A path such as wp-content/plugins/example-plugin/ or wp-content/themes/example-theme/ names the plugin or theme at fault.

"There has been a critical error on this website"

WordPress has caught a PHP fatal error and emails the site's admin address a link to recovery mode.

1. Open the link from the email and sign in. WordPress pauses the plugin or theme that failed, for your browser only, and names it in a notice.
2. Deactivate that plugin (or switch to another theme), then update or replace it.
3. Leave recovery mode with the button in the admin bar.

Verify: the site loads for visitors in a private browser window. If no email came, the debug log from step 1 names the file instead.

A white screen, or you cannot reach the dashboard

1. In wp-content, rename plugins to plugins_old. WordPress then runs without plugins.
2. If the site works now, rename the folder back to plugins, then rename one plugin folder at a time (for example example-plugin to example-plugin.off) until you find the one that breaks the site.
3. If the site is still white, rename the active theme's folder in wp-content/themes. WordPress switches to a default theme such as Twenty Twenty-Five, if one is installed.

Verify: the dashboard opens. Under Plugins, activate the other plugins again one by one.

"Error establishing a database connection"

WordPress cannot sign in to its database. Usually one of the four settings in wp-config.php is wrong:

define( 'DB_NAME', 'database_name_here' );
define( 'DB_USER', 'username_here' );
define( 'DB_PASSWORD', 'password_here' );
define( 'DB_HOST', 'localhost' );

1. In your panel, compare the database name and the database user with DB_NAME and DB_USER. On cPanel both carry your account name as a prefix, for example account_wp1.
2. Check that the user is assigned to that database with all privileges.
3. If you are not sure about the password, set a new one for the database user in the panel and put it in DB_PASSWORD.

See databases and phpMyAdmin. If all four settings are right and the error stays, open a ticket.

"Briefly unavailable for scheduled maintenance. Check back in a minute."

An update stopped before it finished and left the .maintenance file behind. Delete .maintenance in the WordPress root folder (turn on hidden files in File Manager to see it), then run the update again under Dashboard › Updates.

"Allowed memory size of … bytes exhausted"

A plugin or theme needs more PHP memory than allowed.

1. Raise memory_limit for the site in your panel; see PHP version and settings. WordPress keeps the PHP limit when it is higher than its own setting, so this is usually all you need.
2. If wp-config.php sets WP_MEMORY_LIMIT, or a plugin asks you to set it, use a value no higher than your PHP memory_limit, above the "stop editing" line:

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

If the error comes back with more memory, the plugin named in the debug log has a problem; update or replace it.

Posts and pages show 404 errors

Open Settings › Permalinks and click Save Changes without changing anything. WordPress writes its rewrite rules again. If that does not help, check that .htaccess in the WordPress root folder contains this block:

# BEGIN WordPress
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress

A redirect loop after changing the site address

If you changed the addresses under Settings › General and can no longer sign in, set them in wp-config.php. These lines override the values in the database:

define( 'WP_HOME', 'https://example.com' );
define( 'WP_SITEURL', 'https://example.com' );

Use the same https:// address in both, and make sure the certificate is active first; see turn on free SSL and force HTTPS.

Timeouts and slow admin pages

Heavy plugins can ask more of the server than your plan allows. Deactivate the plugins you do not need, switch to a default theme to test, and turn on caching; see LiteSpeed Cache. For 508 errors, see fix 500, 403, 404 and 508 errors.

Next steps

• Prevent the next problem: secure a WordPress site.
• Before big updates: back up and restore your hosting account.