Fatal error: Uncaught mysqli_sql_exception: Unknown database 'register_db' in C:\xampp\htdocs\ProjectAll\Register_System\server.php:9 Stack trace: #0 C:\xampp\htdocs\ProjectAll\Register_System\server.php(9): mysqli_connect('localhost', 'root', Object(SensitiveParameterValue), 'register_db') #1 C:\xampp\htdocs\ProjectAll\Register_System\login.php(1): include('C:\\xampp\\htdocs...') #2 {main} thrown in C:\xampp\htdocs\ProjectAll\Register_System\server.php on line 9