Access Gmail using Google Api - hangs on GoogleWebAuthorizationBroker.AuthorizeAsync...

Hello

I am really struggling to access my gmail account using google api in sharepoint 2013.

My VM configuration:

• Windows server 2012 r2 with latest updates.
• Sharepoint 2013 enterprise with latest updates.
• Visual Studio 2015 Pro

This is the code snippet which works perfectly with windows application or web application on same machine!

   public void ReadEmails()
        {
            try
            {
                SPSecurity.RunWithElevatedPrivileges(delegate()
                {	//Gmail access
                    UserCredential credential;
                    var path = SPUtility.GetVersionedGenericSetupPath(@"TEMPLATE\LAYOUTS\mgClient_secret.json", 15);
                    using (var stream = new FileStream(path, FileMode.Open, FileAccess.Read))
                    {
                        string credPath = @"TEMPLATE\LAYOUTS\Gmail";
                        credPath = Path.Combine(credPath, ".credentials/mgSupportgmail");
                        credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                            GoogleClientSecrets.Load(stream).Secrets,
                           new[] { GmailService.Scope.GmailReadonly },"user",
                            CancellationToken.None,
                            new FileDataStore(credPath, true)).Result;
                        Console.WriteLine("Credential file saved to: " + credPath);
                    }

                    // Create Gmail API service.
                    var service = new GmailService(new BaseClientService.Initializer()
                    {
                        HttpClientInitializer = credential,
                        ApplicationName = ApplicationName,
                    });


                    // Define parameters of request.
                    UsersResource.LabelsResource.ListRequest request = service.Users.Labels.List("me");

                    List<Message> oMails = ListMessages(service, "support@mygmail.co.uk", "label: auto - support");


                });
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                throw;
            }
        }


    public static List<Message> ListMessages(GmailService service, String userId, String query)
        {
            List<Message> result = new List<Message>();
            UsersResource.MessagesResource.ListRequest request = service.Users.Messages.List(userId);
            request.Q = query;

            do
            {
                try
                {
                    ListMessagesResponse response = request.Execute();
                    result.AddRange(response.Messages);
                    request.PageToken = response.NextPageToken;
                }
                catch (Exception e)
                {
                    Console.WriteLine("An error occurred: " + e.Message);
                }
            }
            while (!String.IsNullOrEmpty(request.PageToken));

            return result;
        }
   

 As I mentioned the code works with a win or web project (.Net Framework 4.5 like sharepoint 2013) with same configuration on same machine but if run it in a simple sharepoint project or webpart it just hangs on 

credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                            GoogleClientSecrets.Load(stream).Secrets,
                           new[] { GmailService.Scope.GmailReadonly },"user",
                            CancellationToken.None,
                            new FileDataStore(credPath, true)).Result;

and the Websites show a spinning wheel and never finish loading ...

There is no permission problem to write to folder  credPath.

Would appreciate any advice or suggestions. 

Thanks