PHP Google Adwords：invalid_grant

I have made a request to google adwords and got a refresh token (without using GetRefreshToken.php from the php library). I have copied and pasted the refresh_token, developerToken, client_id and client_secret into the auth.ini file.

But when I run the following part:

$user = new AdWordsUser();

$campaignService = $user->GetService('CampaignService', 'v201603');

// Create selector.
$selector = new Selector();
$selector->fields = array('Id', 'Name');
$selector->ordering[] = new OrderBy('Name', 'ASCENDING');

// Create paging controls.
$selector->paging = new Paging(0, AdWordsConstants::RECOMMENDED_PAGE_SIZE);

// Make the get request.
$page = $campaignService->get($selector);

In return I get the following error:

 OAuth2Exception in SimpleOAuth2Handler.php line 119:
{
"error" : "invalid_grant"
}

The library is: Library. And the SimpleOAuth2Handler.php is here: Oauth

Any ideas why?

Have you tried passing the values directly into the adwords constructor function to make sure they are valid or at least are you setting the customer account number ? . The refresh token is used to obtain an access token which is good for about an hour. Caching this would help performance as you would not need to fetch a new access token every request.

Try adding the following -

$user->SetClientCustomerId('set your account number here');

// also if you are sure your oAuth data is valid 

$user->SetOAuth2Info('pass your oauth data')