Could not create SSL/TLS secure channel. ---> System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel. code example

Example: could not create ssl/tls secure channel

// using System.Net;
ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
// Use SecurityProtocolType.Ssl3 if needed for compatibility reasons