Error while integrating bing ads api in c#

Hi,

I am integrating bing ads api into c# code and I have reference

https://msdn.microsoft.com/en-us/library/bing-ads-reporting-request-and-download-a-keyword-performance-report-in-csharp.aspx

and there is page "ReportingServiceManager.cs"

in that I got error at line no.190 -

response = await apiService.CallAsync((s, r) => s.SubmitGenerateReportAsync(r), submitRequest).ConfigureAwait(false);

and the error is-

Unable to automatically step into the server. Connecting ti the server machine 'api.bingads.microsoft.com' failed