title: Simple graphql client in c# using RestSharp - The underlying connection was closed error
body: <p>I have a graphql server written in NodeJS + ExpressJS + MongoDB, and I can run the following mutation on it fine:</p>
  
  <p><a href="https://i.stack.imgur.com/pgaqj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pgaqj.png" alt="enter image description here"></a></p>
  
  <p>I need to use the graphql api on a C# desktop application. So, I have decided to create a simple GraphQL Client in C#, which looks like this:</p>
  
  <p><a href="https://github.com/latheesan-k/simple-graphql-client/blob/master/SimpleGraphQLClient/SimpleGraphQLClient.cs" rel="nofollow noreferrer">https://github.com/latheesan-k/simple-graphql-client/blob/master/SimpleGraphQLClient/SimpleGraphQLClient.cs</a></p>
  
  <p>I use it like this:</p>
  
  <pre><code>var client = new SimpleGraphQLClient("https://tweetserver.dynamic-dns.net/graphql");
  
  var query = @"
      mutation {
          signup(
              email: $email
              fullName: $fullName
              password: $password
              avatar: $avatar
              username: $username
          ) {
              token
          }
      }
  ";
  
  dynamic signup = client.Execute(query, new
  {
      email = "test-user3@domain.com",
      fullName = "Test User",
      password = "123456",
      avatar = "https://randomuser.me/api/portraits/women/0.jpg",
      username = "testuser3"
  });
  
  if (signup != null &amp;&amp; signup.error == null)
  {
      Console.WriteLine((string)signup.token);
  }
  else
  {
      Console.WriteLine("Error - {0}", signup.error);
  }
  </code></pre>
  
  <p>When I run the tester, I get the following error:</p>
  
  <blockquote>
    <p>Error - The underlying connection was closed: An unexpected error
    occurred on a send.</p>
  </blockquote>
  
  <p>I know the graphql api end point is valid and working as intended (see first screenshot):</p>
  
  <p><a href="https://tweetserver.dynamic-dns.net/graphql" rel="nofollow noreferrer">https://tweetserver.dynamic-dns.net/graphql</a>
  <a href="https://tweetserver.dynamic-dns.net/graphiql" rel="nofollow noreferrer">https://tweetserver.dynamic-dns.net/graphiql</a></p>
  
  <p>Any ideas what might be wrong?</p>