Connecting to a REST webservice in C# - c#

I am not familiar with REST webservices, but I am trying to get a response from one of them in a C# application.
I am trying to connect to the webservice and authenticate my application to get a token. For this, I have an URL, a login and a password.
When I call the authentication method with cURL tool, I get a « success :true» answer, followed with the token string.
But when I try to do the same with my C# code, I always get a « success :false» answer and no token.
Can somebody help me to understand what is missing in my C# code to get the correct answer ? Thank you.
The cURL request (given by the webservice owner) is:
curl -X POST -d "{\"user\":\"mylogin\",\"pwd\":\"mypassword\"}" \
-H "Content-Type: application/json" http://webserviceURL/authenticate
My code is the following : (restlogin, restpassword and resturl are three strings and get the correct values for the connection. The resulting string is obtained in the variable nammed token).
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(resturl + "authenticate");
request.Method = "POST";
request.Credentials = new NetworkCredential(restlogin, restpassword);
request.ContentType = "application/json";
request.Timeout = 30000;
request.ReadWriteTimeout = 30000;
request.Accept = "application/json";
request.ProtocolVersion = HttpVersion.Version11;
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
if (response.StatusCode == HttpStatusCode.OK)
{
using (Stream respStream = response.GetResponseStream())
{
StreamReader reader = new StreamReader(respStream, Encoding.UTF8);
token = reader.ReadToEnd();
reader.Close();
reader.Dispose();
response.Close();
}
}

As per my comment to the question, you are not sending your credentials in the request body. With request.Credentials you're setting the Authentication Header in your HttpRequest.
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(resturl + "authenticate");
request.Method = "POST";
request.ContentType = "application/json";
request.Timeout = 30000;
request.ReadWriteTimeout = 30000;
request.Accept = "application/json";
request.ProtocolVersion = HttpVersion.Version11;
// Set your Response body
using (var streamWriter = new StreamWriter(request.GetRequestStream()))
{
string json = "{\"user\":\"" + restlogin + "\"," +
"\"pwd\":\"" + restpassword + "\"}";
streamWriter.Write(json);
streamWriter.Flush();
streamWriter.Close();
}
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
if (response.StatusCode == HttpStatusCode.OK)
{
using (Stream respStream = response.GetResponseStream())
{
StreamReader reader = new StreamReader(respStream, Encoding.UTF8);
token = reader.ReadToEnd();
reader.Close();
reader.Dispose();
response.Close();
}
}

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EDIT:
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Maybe you can paste your source code here if you need any help with that, so we can look after it
OK! Solution found!
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