Google Analytics APIでトークンを更新する際の「invalid_grant」エラーを解決するにはどうすればよいですか?

$client = new apiClient();
$client->setClientId($config['oauth2_client_id']);
$client->setClientSecret($config['oauth2_client_secret']);
$client->setRedirectUri($config['oauth2_redirect_uri']);
$client->setScopes('https://www.googleapis.com/auth/analytics.readonly');
$client->setState('offline');

$client->setAccessToken($config['token']); // The access JSON object.

$client->refreshToken($config['refreshToken']); // Will return error here

// Retrieve original token from database
$tokenquery = "SELECT * FROM token WHERE type='original'";
$tokenresult = mysqli_query($cxn, $tokenquery);
if ($tokenresult != 0) {
    $tokenrow = mysqli_fetch_array($tokenresult);
    extract($tokenrow);
}
$time_created = json_decode($token)->created;
$t = time();
$timediff = $t - $time_created;

$refreshToken = json_decode($token)->refresh_token;

// Initialize Google client
$client = new Google_Client();
$client->setApplicationName('');
$client->setScopes(array());
$client->setClientId('');
$client->setClientSecret('');
$client->setRedirectUri('');
$client->setAccessType('offline');
$client->setDeveloperKey('');

// Refresh token if expired
if (($timediff > 3600) && ($token != '')) {
    $refreshquery = "SELECT * FROM token WHERE type='refresh'";
    $refreshresult = mysqli_query($cxn, $refreshquery);

    // If refresh token exists
    if ($refreshresult != 0) {
        $refreshrow = mysqli_fetch_array($refreshresult);
        extract($refreshrow);
        $refresh_created = json_decode($token)->created;
        $refreshtimediff = $t - $refresh_created;

        // If refresh token is also expired
        if ($refreshtimediff > 3600) {
            $client->refreshToken($refreshToken);
            $newtoken = $client->getAccessToken();
            $tokenupdate = "UPDATE token SET token='$newtoken' WHERE type='refresh'";
            mysqli_query($cxn, $tokenupdate);
            $token = $newtoken;
            echo "refreshed again";
        } else {
            $client->setAccessToken($token);
            echo "use refreshed token but not time yet";
        }
    } else {
        $client->refreshToken($refreshToken);
        $newtoken = $client->getAccessToken();
        $tokenupdate = "INSERT INTO token (type, token) VALUES ('refresh', '$newtoken')";
        mysqli_query($cxn, $tokenupdate);
        $token = $newtoken;
        echo "refreshed for first time";
    }
}

// If token is still valid
if (($timediff < 3600) && ($token != '')) {
    $client->setAccessToken($token);
}

$service = new Google_DfareportingService($client);