I got this following error "Could not create SSL/TLS secure channel" in your ASP.NET MVC WebClient application.

CODE:
WebClient webClient = new WebClient(); string content = webClient.DownloadString(url); HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(content);
SOLUTION:
Client servers might supported by SSL/TLS protocol versions. So you may specify the SSL/TLS protocol version in your code.
WebClient webClient = new WebClient(); ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; string content = webClient.DownloadString(url); HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(content);