Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Encoder\Base64Encoder' not found in /var/www/typo3/vendor/symfony/mime/Encoder/Base64MimeHeaderEncoder.php:17 Stack trace: #0 {main} thrown in /var/www/typo3/vendor/symfony/mime/Encoder/Base64MimeHeaderEncoder.php on line 17