Content is not show at Facebook wall, got blank page

I'm trying to share content from a CI3 application. I'm using

Code:

"facebook/php-sdk-v4": "4.0.21"

in composer.json file for SDK libraries. This is the code I have based on [this][1] blog post:

PHP Code:

use Facebook\FacebookSession;
    use Facebook\FacebookRequest;
    use Facebook\FacebookRequestException;
    use Facebook\GraphObject;
    
    class ShareFacebook extends CI_Controller
    {
        private $facebookAccessToken;
        private $defaultPermissions = array( 'publish_actions' );
    
        public function __construct()
        {
            parent::__construct();
    
            // Initialize the SDK
            FacebookSession::setDefaultApplication(
                $this->config->item( 'facebook_app_id' ),
                $this->config->item( 'facebook_app_secret' )
            );
    
            $this->facebookAccessToken = new FacebookSession( $this->config->item( 'facebook_app_client_token' ) );
        }
    
        public function index()
        {
            try {
    
                $request = (
                new FacebookRequest(
                    $this->facebookAccessToken, 'POST', '/me/feed', array(
                        'message' => 'User provided message'
                    )
                )
                )->execute();
    
                $response = $request->getGraphObject()->asArray();
                print_r( $response );
            } catch ( FacebookRequestException $e ) {
                echo "Exception occured, code: ".$e->getCode();
                echo " with message: ".$e->getMessage();
            }
        }
    } 


But when I execute the method I got a blank page with no errors in Apache logs or so on and content is not show at my Facebook wall, what I'm missing?

[1]: http://www.benmarshall.me/facebook-sdk-php-v4/