Hello everybody! I am working with the Facebook PHP SDK for the first time. I have created the following code so far and works on the whole:

    <?php
        require_once __DIR__ . '/Facebook/autoload.php'; // change path as needed

        $fb = new \Facebook\Facebook([
          'app_id' => 'MY ID',
          'app_secret' => 'MY SECRET CODE',
          'default_graph_version' => 'v2.17',
          'default_access_token' => 'MY TOKEN', // optional
        ]);

        $postData = "";

        try {
            $response = $fb->get('/MY SITE ID/feed?fields=full_picture,message,permalink_url.limit(10)','MY TOKEN');
        } catch(Facebook\Exceptions\FacebookResponseException $e) {
            echo 'Graph returned an error: ' . $e->getMessage();
            exit;
        } catch(Facebook\Exceptions\FacebookSDKException $e) {
            echo 'Facebook SDK returned an error: ' . $e->getMessage();
            exit;
        }

        $graphNode = $response->getGraphEdge();


        if (! empty($graphNode)) {
            foreach ($graphNode as $k => $v) {

                ?>
                <div class="grid-item pNormal" data-timestamp="<?php echo $graphNode[$k]["created_time"]; ?>">
                    <div class="grid-item-content">
                        <article id="post-<?php echo $graphNode[$k]["id"]; ?>">
                            <a href="<?php echo $graphNode[$k]["permalink_url"]; ?>"> 
                                <div class="grid-item-thumbnail">
                                    <img src="<?php echo $graphNode[$k]["full_picture"]; ?>" alt="" class="img-fluid">    
                                </div>
                                <header class="sl-entry-header">
                                    Musterüberschrift
                                </header>
                                <div class="sl-entry-content">
                                    <?php echo $graphNode[$k]["message"]; ?>
                                </div>
                                <div class="pCats">
                                    Musterkategorien
                                </div>
                            </a>
                        </article>
                    </div>
                </div>
                <?php
            }
        }
        ?>

With "" I would like to output the current timestamp of the post. However, the field is always empty for me and nothing is simply output.

Can anyone help me further?