First Display flash Message and then Redirect


I want first in a submit form , first to display one flash message , when is a success , and then redirect.
Currently, It redirects , but it does not displaying the flash message.

How ,to first display the flash message and then to redirect?

In the controller:

      if ($order->validate()) {
                    Yii::$app->session->setFlash('success', "Order is made!!");
                    return $this->redirect('index');
                } else {
                    die(var_dump($order->errors, true));

In the view:

<?php if (Yii::$app->session->hasFlash('success')): ?>
    <div class="alert alert-success alert-dismissable">
        <button aria-hidden="true" data-dismiss="alert" class="close" type="button">×</button>
        <?= Yii::$app->session->getFlash('success') ?>

<?php endif; ?>

ANy help is much appreciated!

Do you have this in index view?