Twitter LogIn doesn't work. Invalid and Expired token

Question

I follow this code and I use thid library http://hayageek.com/login-with-twitter/

Log in works but I think that the oauth token that the program generates are bad. This is my problem and I don't know how I can resolve:

$connection = new TwitterOAuth($CONSUMER_KEY, $CONSUMER_SECRET);

$request_token = $connection->getRequestToken($OAUTH_CALLBACK); //get Request Token

if( $request_token)
{
    echo print_r($request_token);
    $token = $request_token['oauth_token'];

    $_SESSION['oauth_token'] = $token = $request_token['oauth_token'];
    $_SESSION['oauth_token_secret'] = $request_token['oauth_token_secret'];


    switch ($connection->http_code) 
    {
        case 200:
            $url = $connection->getAuthorizeURL($token);
            //redirect to Twitter .
            header('Location: ' . $url); 
            break;
        default:
            echo "Coonection with twitter Failed";
            break;
    }

}
else //error receiving request token
{
    echo "Error Receiving Request Token";
}


 and after log in the page the callback page do this:

    $connection = new TwitterOAuth(CONSUMER_KEY, CONSUMER_SECRET, $_SESSION['oauth_token'], $_SESSION['oauth_token_secret']);
    /
     $content = $connection->get ( "account/verify_credentials" );

Now I obtain "Invalid and expiried token". Anyone can help me?