If your wordpress site is suddenly giving blank white screen with no error then it does not mean there are no errors. Its possible your server environment in suppressing display of errors on screen or error reporting is completely disabled.
In order to fix wordpress blank white screen you first need to know the core problem.
Check if there is error_log or similar file in wordpress site root directory, If file exist then check that file for actual error. If you see no error log file then its time to use WordPress Debug mode.
Simply open your site wp-config.php and look for section with titleFor developers: WordPress debugging mode.
Find define(‘WP_DEBUG’, false); in wp-config and change it to
define('WP_DEBUG', true);
This will enable debug mode and you will see actual errors on screen.
You should ignore Notice and look for Fatal errors which will be causing White screen, they can be missing plugin/template files or even database connectivity issues.