Fatal error: Uncaught Error: Class "Symfony\Component\Config\Definition\Dumper\YamlReferenceDumper" not found in /var/www/html/phpkobo/research/php-downloaded-apps/phpmailer-5-2-16/PHPMailer-5.2.16/vendor/symfony/config/Definition/ReferenceDumper.php:22 Stack trace: #0 {main} thrown in /var/www/html/phpkobo/research/php-downloaded-apps/phpmailer-5-2-16/PHPMailer-5.2.16/vendor/symfony/config/Definition/ReferenceDumper.php on line 22