Yii2 API initialization. Behavior () Doesn't work

I am creating a restful api in yii2. I ran into a problem here. In my userController.php, I created a behavior () for authentication.

use yii\filters\auth\HttpBasicAuth;

public function behaviors()
{
    $behaviors = parent::behaviors();
    $behaviors['authenticator'] = [
        'class' => HttpBasicAuth::className(),
        'except' => ['signup']
    ];
    return $behaviors;
}

      

        
        
        
      

    

This is where I went through 'except' => ['signup']

, so authentication shouldn't be applied to the "signup" action.

But it doesn't apply here and asks for authentication for the "signup" action.

So please guide where I went wrong.