Fatal error: Uncaught Error: Interface "Symfony\Component\Mailer\Transport\TransportInterface" not found in /var/www/html/lib/pkp/classes/mail/transport/PHPMailerTransport.php:28 Stack trace: #0 {main} thrown in /var/www/html/lib/pkp/classes/mail/transport/PHPMailerTransport.php on line 28