Fix bugs: White page, Blank Page in magento

In file index.php. You recomment // ini_set('display_errors', 1);
Result: ini_set('display_errors', 1);

Check erros code of white page. Make sure codes of Core Magento, Modules, ... are true.

Clear cache, Reindex in Admin magento. Remove caches in magento/var/cache/*

FINAL: Permision files of magento. Link
https://letunhatkong.blogspot.com/2015/07/permission-file-and-folder-in-magento.html

Permission file and folder in Magento

sudo find /var/www/html/magentoInstallationFolder/ -type d -exec chmod 775 {} \;

sudo find /var/www/html/magentoInstallationFolder/ -type f -exec chmod 664 {} \;

sudo find -type d -exec chmod 775 {} \;

sudo find -type f -exec chmod 664 {} \;

Set Writable for 3 folders in root magento: var, media, app/etc
sudo chmod -R 777 var/  media/ app/etc/ downloader/

Done. Good Luck!

==== Magento UseGuide ====

find . -type f -exec chmod 400 {} \;
find . -type d -exec chmod 500 {} \; 
find var/ -type f -exec chmod 600 {} \; 
find media/ -type f -exec chmod 600 {} \;
find var/ -type d -exec chmod 700 {} \; 
find media/ -type d -exec chmod 700 {} \;
chmod 700 includes
chmod 600 includes/config.php