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