Fatal error: Uncaught Error: Class 'JMS\Serializer\AbstractVisitor' not found in /home/lafaamicps/www/symfony/vendor/jms/serializer/src/JMS/Serializer/XmlSerializationVisitor.php:30 Stack trace: #0 {main} thrown in /home/lafaamicps/www/symfony/vendor/jms/serializer/src/JMS/Serializer/XmlSerializationVisitor.php on line 30