Fatal error: Uncaught Error: Class "App\Engine\LegacyHandler\LegacyHandler" not found in /var/www/html/core/backend/Install/LegacyHandler/Upgrade/AddNewConfigEntriesHandler.php:37 Stack trace: #0 {main} thrown in /var/www/html/core/backend/Install/LegacyHandler/Upgrade/AddNewConfigEntriesHandler.php on line 37