Fatal error: Uncaught Error: Class "Symfony\Component\Mailer\Transport\RoundRobinTransport" not found in D:\xampp\htdocs\dropifypro\vendor\symfony\mailer\Transport\FailoverTransport.php:19 Stack trace: #0 {main} thrown in D:\xampp\htdocs\dropifypro\vendor\symfony\mailer\Transport\FailoverTransport.php on line 19