Webclient POST 405 Error in API

Question

I've written some code a while back that handles POST requests. Suddenly it stopped working whilst I changed nothing in either the API (It still works fine with postman) nor the C# code. But I get a 405 error (method not allowed) when I run my code. The login method:

public byte[] logInViaAPI(string email, string password)
        {
            var response = APIHandler.Post("http://myurlhere", new NameValueCollection() {
                {   "email", email          },
                {   "password", password    },
            });
            return response;
        }

This is my POST method:

public static byte[] Post(string uri, NameValueCollection pairs)
        {
            byte[] response = null;
            try
            {
                using (WebClient client = new WebClient())
                {

                    response = client.UploadValues(uri, pairs); //This is where I get my error
                }
            }
            catch (WebException ex)
            {
                Console.Write(ex);
                return null;
            }
            return response;
        }

The error:

An unhandled exception of type 'System.Net.WebException' occurred in System.dll

Additional information:

The remote server returned an error: (405) Method Not Allowed.

I used HTTP request with post as a source (and some other topics too) but I cant seem to figure out the problem.

Answer 1

Found the answer to my own question: I changed to protocol to HTTPS from HTTP, whilst still using the HTTP url.

Answer 2

Another possible solution is the use SecurityProtocol. Try this before the call:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;