White screen or critical error

A white screen or “There has been a critical error on this website” means PHP stopped with an error. The debug log shows the reason; the most common ones are a conflicting plugin and a low memory limit.

1. Turn on the debug log

Add these lines to wp-config.php in the root of your site (via FTP or your host’s file manager). If WP_DEBUG is already there, change it to true:

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

Reload the broken page — the error is written to wp-content/debug.log. You can also read it with the Log Viewer plugin. Attach this file when you contact support.

2. Deactivate a plugin via FTP

If the dashboard doesn’t open, turn plugins off from the server:

1. Connect via FTP and open wp-content/plugins/.
2. Rename the folder of the plugin from the error (or of the last updated plugin), e.g. add -off to the name — WordPress deactivates it.
3. Reload the site. To remove the plugin completely, delete its folder.

3. Increase the memory limit

An “Allowed memory size exhausted” error means WordPress needs more memory. Try these one by one:

wp-config.php — before the line “That’s all, stop editing!”:

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

php.ini — if you have access to it:

memory_limit = 256M

.htaccess — at the top of the file in the site root:

php_value memory_limit 256M

Nothing helped? Ask your hosting provider to increase the memory limit.