仅在调试时工作，但不在运行中工作

我正试图运行此代码从google api中获取位置，但有一次它运行良好。当我尝试pagetoken时，它不起作用，并给了我无效的请求。但如果我在调试中运行它，那么有时它运行得很好，有时则不然。你能帮忙吗？

private string request_google(string link)
    {
        try
        {
           // link = HttpUtility.ParseQueryString(link).ToString();
            HttpWebRequest webRequest = WebRequest.Create(link) as HttpWebRequest;
            webRequest.Timeout = 20000;
            webRequest.Method = "GET";
            var response = (HttpWebResponse)webRequest.GetResponse();
            using (var stream = response.GetResponseStream())
            {
                var r = new StreamReader(stream);
                string responce = r.ReadToEnd();
                file_number = file_number + 1;
                File.WriteAllText("E:''google maps''pharmcy''places_" + string.Format("text-{0:yyyy-MM-dd_hh-mm-ss-tt-fff}",
                  DateTime.Now) + "_file" + file_number + " _area_" + area_number + ".txt", responce);

                dynamic places_reponce = JsonConvert.DeserializeObject(responce);
                if (places_reponce.status == "INVALID_REQUEST")
                {
                    File.WriteAllText("E:''google maps''pharmcy''places_" + string.Format("text-{0:yyyy-MM-dd_hh-mm-ss-tt-fff}",
             DateTime.Now) + "_file" + file_number + " _area_" + area_number + "invalid_reques" + ".txt", "The link :" + link);
                }

                return places_reponce.next_page_token;

            }
        }
        catch (Exception e)
        {
            File.WriteAllText("E:''google maps''pharmcy''places_" + string.Format("text-{0:yyyy-MM-dd_hh-mm-ss-tt-fff}",
                 DateTime.Now) + "_file" + file_number + " _area_" + area_number +"error"+ ".txt", "The link :"+link+"'n The Error"+e.ToString());
            return null;
        }

    }