Fatal error: Uncaught Error: Class 'Whoops\Handler\Handler' not found in E:\xampp\htdocs\www\yunwei\qr2500\vendor\filp\whoops\src\Whoops\Handler\CallbackHandler.php:16 Stack trace: #0 {main} thrown in E:\xampp\htdocs\www\yunwei\qr2500\vendor\filp\whoops\src\Whoops\Handler\CallbackHandler.php on line 16