how to solve 403 error in google analytics api call

Question

I'm using the code in the following post: Google Analytics API - Programmatically fetch page views in server side

but getting a 403 forbidden error on the highlighted line below. I don't think it's a credential issue, becuase my credentials are correct, as I have checked and double checked, and also I log in to the analytics account with these credentials. So maybe it is somekind of folder permissions issue ?

//-------------- Get Auth Token -------------------

WebClient webClient = new WebClient();
NameValueCollection data = new NameValueCollection();
data.Add("accountType", "GOOGLE");
data.Add("Email", "xxxx@gmail.com");
data.Add("Passwd", "xxxx");//Passwd, not a misspell.
data.Add("service", "analytics");
data.Add("source", "xxxx-xxxx-xx");//Could be anything.

byte[] bytes = webClient.UploadValues("https://www.google.com/accounts/ClientLogin", "POST", data);
string tokens = Encoding.UTF8.GetString(bytes);
string authToken = extractAuthToken(tokens);

//-------------- Get page views -------------------

string feed = "https://www.google.com/analytics/feeds/data";

//Required:
string ids = "ga:xxxx";
string metrics = "ga:pageviews";
string startDate = "2011-06-25";
string endDate = "2011-07-25";

//Optional:
string dimensions = "ga:pagePath";
string sort = "-ga:pageviews";            

string feedUrl = string.Format("{0}?ids={1}&dimensions={2}&metrics={3}&sort={4}&start-date={5}&end-date={6}",
    feed, ids, dimensions, metrics, sort, startDate, endDate);

webClient.Headers.Add("Authorization", "GoogleLogin " + authToken);

// This is the line I get the 403 error on:
**string result = webClient.DownloadString(feedUrl);**

//-------------- Extract data from xml -------------------

XDocument xml = XDocument.Parse(result);
var ns1 = "{http://www.w3.org/2005/Atom}";
var ns2 = "{http://schemas.google.com/analytics/2009}";

var q = from entry in xml.Descendants()
        where entry.Name == ns1 + "entry"
        select new
        {
            PagePath = entry.Element(ns2 + "dimension").Attribute("value").Value,
            Views = entry.Element(ns2 + "metric").Attribute("value").Value
        };

//-------------- Do something with data -------------------
foreach (var page in q)
{
    Debug.WriteLine(page.PagePath + " " + page.Views);                
}

//-------------- Help Method -------------------
private string extractAuthToken(string data)
{          
    var tokens = data.Split(new string[] { "\n" }, StringSplitOptions.RemoveEmptyEntries);            
    return tokens.Where(token => token.StartsWith("Auth=")).Single();
}

Answer 1

If you call the Google Analytics API too frequently, you could get 403 Forbidden errors. From that link:

General Analytics API quotas. These apply to both the Analytics APIs, i.e., Management API and Core Reporting API:
- 50,000 requests per project per day
- 10 queries per second (QPS) per IP

I've seen 403 errors returned from the AdWords API when my applications have made too many consecutive calls, so that potentially could be the cause of your problem.

EDIT

If you're not able to make any calls at all, then review the steps listed here under "Before You Begin". According to the documentation, you'll need to register your application through the Google API console before you can use the API.