Fatal error: Uncaught Error: Class "Symfony\Component\Mailer\Transport\AbstractTransport" not found in C:\WebServer\htdocs\bookshelf\vendor\symfony\mailer\Transport\NullTransport.php:21 Stack trace: #0 {main} thrown in C:\WebServer\htdocs\bookshelf\vendor\symfony\mailer\Transport\NullTransport.php on line 21