A completely blank page means PHP stopped part-way through and had nothing to show. The page source will be empty too. It is almost always a fatal error that is being hidden rather than displayed.
See the actual error
Do not guess. Look for an error_log file in your public_html or in wp-content, or open Errors in cPanel. The fatal error will be there with a file name and a line number, which usually names the plugin or theme responsible outright.
If nothing is being logged, temporarily add this to wp-config.php above the line that says to stop editing:
define( 'WP_DEBUG', true ); define( 'WP_DEBUG_LOG', true ); define( 'WP_DEBUG_DISPLAY', false );
Errors then go to wp-content/debug.log. Turn this off again afterwards – leaving it on fills the disk and can expose paths.
The usual causes
- A plugin or theme update that has just run. This is the most common by far.
- A PHP version change leaving code that no longer runs. Switch back and the site returns.
- Exhausted memory, which produces a specific "allowed memory size exhausted" message in the log.
- An edit to a theme file with a syntax error – a missing bracket or semicolon.
Getting back in
If you cannot reach wp-admin, rename the offending plugin's folder in wp-content/plugins using File Manager. WordPress cannot load a plugin whose folder has vanished, so it deactivates it and the site returns. If you do not know which, rename the whole plugins folder to plugins-off, get in, then rename it back and reactivate one at a time.
For a broken theme, switch to a default theme by renaming its folder the same way.
