Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Part\AbstractPart' not found in D:\xampp\htdocs\psp\backend\vendor\symfony\mime\Part\SMimePart.php:19 Stack trace: #0 {main} thrown in D:\xampp\htdocs\psp\backend\vendor\symfony\mime\Part\SMimePart.php on line 19