Error Paypal sandbox: The request was aborted: Could not create SSL/TLS secure channel

Question

I am getting error "The request was aborted: Could not create SSL/TLS secure channel." in case of sandbox however this works with my live credentials.

here is the code snippet

            var uri = new Uri(url);
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
            var request = WebRequest.Create(uri);
            var encoding = new UTF8Encoding();
            var requestData = encoding.GetBytes(postData);

            request.ContentType = "application/x-www-form-urlencoded";
            request.Method = "POST";
            request.Timeout = (300 * 1000); //TODO: Move timeout to config
            request.ContentLength = requestData.Length;

            using (var stream = request.GetRequestStream())
            {
                stream.Write(requestData, 0, requestData.Length);
            }

            var response = request.GetResponse();

            string result;

            using (var reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII))
            {
                result = reader.ReadToEnd();
            }

            return result;

Answer 1

The problem is C# defaults to SSL3 when trying to connect to the PayPal server, which PayPal doesn't accept. PayPal requires the (more secure) TLS 1.2 as a minimum.

You set this through the following code:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;