error : PDOException: SQLSTATE[HY000] [2002] Connection refused in /var/www/html/simulator/application/core/controller.php:15 Stack trace: #0 /var/www/html/simulator/application/core/controller.php(15): PDO->__construct('mysql:host=nemo...', 'root', 'nemolabs1234', Array) #1 /var/www/html/simulator/application/core/controller.php(10): Controller->dbConnect() #2 /var/www/html/simulator/application/core/application.php(13): Controller->__construct() #3 /var/www/html/simulator/public/index.php(26): Application->__construct() #4 {main}//Database connection could not be established.