Fatal error: Uncaught Error: Class 'Symfony\Component\Notifier\FlashMessage\AbstractFlashMessageImportanceMapper' not found in C:\xampp\htdocs\plugins\Symfony\Component\Notifier\FlashMessage\DefaultFlashMessageImportanceMapper.php:19 Stack trace: #0 {main} thrown in C:\xampp\htdocs\plugins\Symfony\Component\Notifier\FlashMessage\DefaultFlashMessageImportanceMapper.php on line 19