Fatal error: Uncaught Error: Class 'yii\helpers\StringHelper' not found in /opt/lampp/htdocs/123playnow-external/vendor/dmstr/yii2-adminlte-asset/gii/templates/crud/simple/controller.php:13 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/123playnow-external/vendor/dmstr/yii2-adminlte-asset/gii/templates/crud/simple/controller.php on line 13