I get error when i use conn.GetCap

[Sami]

I'm getting message "There is an error in XML document (1, 2)." when i try to get server cap. I'm not sure if i miss something here

        string server_URL = "https://server.asmx";
        string server_username = "username";
        string server_password = "passowrd";
        WITSMLWebServiceConnection conn = new WITSMLWebServiceConnection(server_URL, WMLSVersion.WITSML131);
        conn.Username = server_username;
        conn.SetPassword(server_password);
        conn.Proxy = new WebProxy();
        conn.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;
        CapServer cap = conn.GetCap<CapServer>();