Fatal error: Uncaught Error: Class 'Symfony\Component\Config\Definition\Exception\Exception' not found in /home/app/htdocs/ninja/vendor/symfony/config/Definition/Exception/UnsetKeyException.php:20 Stack trace: #0 {main} thrown in /home/app/htdocs/ninja/vendor/symfony/config/Definition/Exception/UnsetKeyException.php on line 20