跳转到服务器报400错误，大家帮我看看有啥错误

Question

这是后台代码，前台没有任何操作。。。。。。 public partial class cb : System.Web.UI.Page    {        JavaScriptSerializer js = new JavaScriptSerializer();        protected void Page_Load(object sender, EventArgs e)        {            string code = Request.QueryString["code"].ToString();            if (!string.IsNullOrEmpty(code))            {                string appkey = ConfigurationManager.AppSettings["appkey"];                string secret = ConfigurationManager.AppSettings["secret"];                string redirect_uri = ConfigurationManager.AppSettings["redirect_uri"];                //code = Request.QueryString["code"].ToString();                WebUtils webUtils = new WebUtils();                IDictionary<string, string> pout = new Dictionary<string, string>();                pout.Add("grant_type", "authorization_code");                pout.Add("client_id", appkey);                pout.Add("client_secret", secret);                pout.Add("code", code);                pout.Add("redirect_uri", redirect_uri);                // 沙箱                string output = webUtils.DoPost("https://oauth.tbsandbox.com/token", pout);                // 正式                //string output = webUtils.DoPost("https://oauth.taobao.com/token", pout);                cbModel cbmodel = js.Deserialize<cbModel>(output);                // Access token                string sessionKey = cbmodel.access_token;                // Access token过期时间                long expires_in = cbmodel.expires_in;                Application["SessionKey"] = sessionKey;                Application["ExpiresIn"] = expires_in;            }        }    }

Answer 1

 webUtils.DoPost("https: 

出错了。

Answer 2

配置问题。