Call external WS withing plugin

Hello ,

I need to call an external webapi thought get method withing plugin.

I am using dynamics on premise and the plugin is sandbox registered.,but i am getting an error : cannot connect to the remote server .

A sample code :

var uri = new Uri("http:......../api/v1/contact");

var request = WebRequest.Create(uri);

request.Method = WebRequestMethods.Http.Get;

request.Timeout = 20000;

request.Headers.Add("DENTITY:{login:login1,password:pass1}");

request.ContentType = "application/json";
try
{

string helloWorldString = "";

using (var response = request.GetResponse())
{

using (var reader = new StreamReader(response.GetResponseStream()))
{

string tmp = reader.ReadToEnd();
helloWorldString = JsonConvert.DeserializeObject<string>(tmp);
Debug.Print("I read this string {0}: ", helloWorldString);
}
}

}
catch (Exception ex)
{
throw;
}