Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Header\UnstructuredHeader' not found in C:\Apache24\htdocs\test-project-sym\vendor\symfony\mailer\Header\MetadataHeader.php:19 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\test-project-sym\vendor\symfony\mailer\Header\MetadataHeader.php on line 19