Fatal error: Uncaught Error: Class "Symfony\Component\Mailer\Transport\RoundRobinTransport" not found in /usr/www/unityweb/public/hms/vendor/symfony/mailer/Transport/FailoverTransport.php:19 Stack trace: #0 {main} thrown in /usr/www/unityweb/public/hms/vendor/symfony/mailer/Transport/FailoverTransport.php on line 19