Fatal error: Uncaught Error: Class "JMS\Serializer\AbstractVisitor" not found in /var/www/html/src/vendor/jms/serializer/src/XmlSerializationVisitor.php:19 Stack trace: #0 {main} thrown in /var/www/html/src/vendor/jms/serializer/src/XmlSerializationVisitor.php on line 19