Fatal error: Uncaught Error: Class "Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer" not found in /var/www/html/drupal/vendor/symfony/serializer/Normalizer/ObjectNormalizer.php:32 Stack trace: #0 {main} thrown in /var/www/html/drupal/vendor/symfony/serializer/Normalizer/ObjectNormalizer.php on line 32