Fatal error: Uncaught Error: Class "Symfony\Component\Mime\Encoder\Base64Encoder" not found in /srv/www/sites/public/starter-cms/vendor/symfony/mime/Encoder/Base64MimeHeaderEncoder.php:17 Stack trace: #0 {main} thrown in /srv/www/sites/public/starter-cms/vendor/symfony/mime/Encoder/Base64MimeHeaderEncoder.php on line 17