Fatal error: Uncaught mysqli_sql_exception: Access denied for user 'root'@'localhost' (using password: NO) in C:\xampp\htdocs\test\db.php:15 Stack trace: #0 C:\xampp\htdocs\test\db.php(15): mysqli->__construct('127.0.0.1', 'root', '', 'demo') #1 {main} thrown in C:\xampp\htdocs\test\db.php on line 15