Fatal error: Uncaught Error: Interface "Kreait\Firebase\Database\Query\Modifier" not found in C:\xampp\htdocs\www\prohelp\vendor\kreait\firebase-php\src\Firebase\Database\Query\Sorter.php:7 Stack trace: #0 {main} thrown in C:\xampp\htdocs\www\prohelp\vendor\kreait\firebase-php\src\Firebase\Database\Query\Sorter.php on line 7