C# The request was aborted: Could not create SSL/TLS secure

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

 ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls
                   | SecurityProtocolType.Tls11
                   | SecurityProtocolType.Tls12
                   | SecurityProtocolType.Ssl3;

//Add this line of code before RestClient
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;