Fatal error: Uncaught Error: Class "Symfony\Component\Mime\Header\AbstractHeader" not found in C:\PHP\APPS\dev\aictec_license_web\vendor\symfony\mime\Header\MailboxListHeader.php:22 Stack trace: #0 {main} thrown in C:\PHP\APPS\dev\aictec_license_web\vendor\symfony\mime\Header\MailboxListHeader.php on line 22