Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Header\AbstractHeader' not found in /home/noct-c/www/tanakahashi/vendor/symfony/mime/Header/UnstructuredHeader.php:21 Stack trace: #0 {main} thrown in /home/noct-c/www/tanakahashi/vendor/symfony/mime/Header/UnstructuredHeader.php on line 21