Updated Google Analytic API and older version - asp.net

Question

Before Google Analytic Update there api this code works.
string userName = GAEmailAddress.ToString();//Its From Database
string passWord = GAPassword.ToString();//Its From Database
const string dataFeedUrl = "https://www.google.com/analytics/feeds/data";
AccountQuery query = new AccountQuery();
AnalyticsService service = new AnalyticsService("AnalyticsApp");
if (!string.IsNullOrEmpty(userName))
{
service.setUserCredentials(userName, passWord);
}
string str = "";
try
{
AccountFeed accountFeed = service.Query(query);
foreach (AccountEntry entry in accountFeed.Entries)
{
str = entry.ProfileId.Value;
}
DataQuery query1 = new DataQuery(dataFeedUrl);
// Bounce Rate Calculations
query1.Ids = str;
query1.Metrics = "ga:visits,ga:bounces";//visitors
query1.Sort = "ga:visits";
query1.GAStartDate = DateTime.Now.AddMonths(-1).AddDays(-2).ToString("yyyy-MM-dd");
query1.GAEndDate = DateTime.Now.AddDays(-3).ToString("yyyy-MM-dd");
query1.StartIndex = 1;
//Others code and other data for bound
I search in SO and and Find this link.
gapi account data url goes to 404
I replace this link :
const string dataFeedUrl = "https://www.google.com/analytics/feeds/data";
with:
https://www.googleapis.com/analytics/v2.4/management/accounts?start-index=1&max-results=100&key=API_KEY
But I still I gett error:
Execution of request failed: https://www.google.com/analytics/feeds/accounts/default
I still search and find this link:
https://developers.google.com/analytics/devguides/reporting/core/v2/#register
As link says I replace :
https://www.googleapis.com/analytics/v2.4/data
But still I got error ? What I am missing here? Thanks.