Fatal error: Uncaught Error: Undefined constant "NO_HEADER" in C:\inetpub\wwwroot\Notebook\includes\header.php:1 Stack trace: #0 C:\inetpub\wwwroot\Notebook\login.php(5): require_once() #1 {main} thrown in C:\inetpub\wwwroot\Notebook\includes\header.php on line 1