using System;

//using Microsoft.AspNetCore.Http.Extensions; 

using System.Net.Http;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var client = new HttpClient();

        var data=client.PostAsync("https://processmapmobile.weyer.com/", new StringContent("{\"Username\": \"MathieuR\", \"Password\": \"!Pr0ce$$M8p!\"}", Encoding.UTF8, "application/json"));

        Console.WriteLine(data.Result);

    }

}