Fatal error: Uncaught Error: Interface "Symfony\Component\DependencyInjection\ContainerInterface" not found in /home/www/drupal8/test/core/lib/Drupal/Component/DependencyInjection/Container.php:47 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Component/DependencyInjection/Container.php on line 47