A blank white page, or WordPress’s There has been a critical error on this website, means PHP hit a fatal error and stopped. The cause is nearly always a plugin, the theme, or PHP running out of memory.
1. Check your email
WordPress emails the site administrator when a fatal error happens, with a recovery mode link that logs you in with the faulty plugin paused. Use it to deactivate or update the plugin it names.
2. Turn on the debug log
Add these lines to wp-config.php above “That’s all, stop editing”:
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );Reload the page, then read wp-content/debug.log. The fatal error line names the file, and the folder name tells you which plugin or theme. Set WP_DEBUG back to false afterwards.
3. Switch plugins off without the dashboard
Over SSH or SFTP, rename the plugins folder:
cd wp-content
mv plugins plugins-offIf the site returns, rename it back and rename plugin folders one at a time to find the culprit. With WP-CLI:
wp plugin deactivate --all
wp plugin activate plugin-name4. Switch to a default theme
wp theme activate twentytwentyfiveIf that fixes it, the theme is at fault.
5. Memory exhausted
Allowed memory size of … bytes exhausted in the log means PHP’s memory limit is too low. Raise it in wp-config.php:
define( 'WP_MEMORY_LIMIT', '256M' );If the server’s own memory_limit is lower, raise that in php.ini too.
Only the admin is white
Often a plugin conflict that only loads in the dashboard. The same steps apply. See also 500 Internal Server Error.
Something out of date? Software changes. If a step no longer works, tell us and we will check it and update the page.
