Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Header\UnstructuredHeader' not found in /home/supporta/public_html/vendor/symfony/postmark-mailer/Transport/MessageStreamHeader.php:16 Stack trace: #0 {main} thrown in /home/supporta/public_html/vendor/symfony/postmark-mailer/Transport/MessageStreamHeader.php on line 16