Fatal error: Uncaught Error: Class 'yii\bootstrap\Widget' not found in C:\xampp\htdocs\web\yii\basic\vendor\yiisoft\yii2-bootstrap\src\NavBar.php:40 Stack trace: #0 {main} thrown in C:\xampp\htdocs\web\yii\basic\vendor\yiisoft\yii2-bootstrap\src\NavBar.php on line 40