Fatal error: Uncaught Error: Class 'Drupal\Core\Installer\InstallerKernel' not found in /var/www/html/web/core/includes/errors.inc:311 Stack trace: #0 /var/www/html/web/core/includes/errors.inc(125): _drupal_get_error_level() #1 /var/www/html/web/core/includes/bootstrap.inc(638): error_displayable() #2 /var/www/html/web/core/includes/bootstrap.inc(622): _drupal_exception_handler_additional(Object(Error), Object(Error)) #3 [internal function]: _drupal_exception_handler(Object(Error)) #4 {main} thrown in /var/www/html/web/core/includes/errors.inc on line 311