Fatal error: Uncaught Error: Class "Symfony\Component\Mime\Header\AbstractHeader" not found in /home/matrixweb/public_html/whmcs2022/whmcs/vendor/symfony/mime/Header/MailboxHeader.php:22
Stack trace:
#0 {main}
thrown in /home/matrixweb/public_html/whmcs2022/whmcs/vendor/symfony/mime/Header/MailboxHeader.php on line 22