PHP Fatal error: Class 'PDO' not found
try
yum install php-pdo yum install php-pdo_mysql service httpd restart
Try adding use PDO; after your namespace or just before your class or at the top of your PHP file.
This can also happen if there is a php.ini file in the web app's current working directory. If one has been placed there to change certain settings, it will override the global one.
To avoid this problem, don't use a php.ini file to change settings; instead you can: