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