Nothing but white.
WHAT IT MEANS
A fatal error occurred and the error message is not being displayed.
WHERE TO LOOK FIRST
The error log, in cPanel.
It names the file and line.
THE MOST COMMON CAUSES
A plugin or theme conflict A PHP memory limit reached A PHP version incompatibility Corrupted files after a failed update
HOW TO TEST FOR A PLUGIN CAUSE
Rename the plugins directory in File Manager.
That disables all of them. If the site returns, a plugin is responsible.
Rename it back and disable them individually.
HOW TO TEST FOR A THEME CAUSE
Rename the active theme's folder.
The site falls back to a default theme.
FOR A MEMORY LIMIT
Raise it in the PHP settings, and establish what consumed it.
FOR A PHP VERSION PROBLEM
Switch back to the previous version and check compatibility.
WHAT TO DO FIRST
Read the error log.
Guessing without it wastes hours.