Fatal error: Uncaught Error: Class "Drupal\Core\Config\Entity\ConfigEntityBundleBase" not found in /home/www/drupal8/test/core/modules/contact/src/Entity/ContactForm.php:55
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/contact/src/Entity/ContactForm.php on line 55