WebClient.DownloadData method crashing the application

Question

This below is all my code which is a copy paste from Web API book I am reading.

public class PageSizeController : ApiController
{
    private static string TargetUrl = "http://apress.com";

    public long GetPageSize()
    {
        WebClient wc = new WebClient();
        Stopwatch sw = Stopwatch.StartNew();
        byte[] apressData = wc.DownloadData(TargetUrl);
        Debug.WriteLine("Elapsed Time: ", sw.ElapsedMilliseconds);
        return apressData.LongLength;
        }
    }
}

When I make the API call : http://localhost:38000/api/pagesize

It throw this exception on DownloadData method:

System.Net.WebException: 'The request was aborted: Could not create SSL/TLS secure channel.'

This is not very welcoming when you open a book to follow the examples and it just doesn't work for their HelloWorld application.