Fatal error: Uncaught Error: Class "Drupal\Core\Installer\InstallerKernel" not found in /opt/drupal/web/core/includes/errors.inc:323 Stack trace: #0 /opt/drupal/web/core/includes/errors.inc(123): _drupal_get_error_level() #1 /opt/drupal/web/core/includes/bootstrap.inc(204): error_displayable() #2 /opt/drupal/web/core/includes/bootstrap.inc(188): _drupal_exception_handler_additional(Object(Error), Object(Error)) #3 [internal function]: _drupal_exception_handler(Object(Error)) #4 {main} thrown in /opt/drupal/web/core/includes/errors.inc on line 323