在真实设备Xamarin表单上获取请求

如何解决在真实设备Xamarin表单上获取请求

iPhone模拟器在收到请求时会接收数据，但物理设备未接收到数据，有人可以告诉我可能是什么问题吗？

public List<Photo> GetPhotoSearch(double northEastLatitude,double northEastLongtitude,double southWestLatitude,double southWestLongtitude)
        {
            List<Photo> photos = new List<Photo>();

            WebRequest request = WebRequest.Create($"{totalUrl}/northEast='{northEastLatitude}'-'{northEastLongtitude}'" +
                                                   $"_southWest='{southWestLatitude}'-'{southWestLongtitude}'");
            WebResponse response = request.GetResponse();
            using (Stream stream = response.GetResponseStream())
            {
                using (StreamReader reader = new StreamReader(stream))
                {
                    string line = "";
                    while ((line = reader.ReadLine()) != null)
                    {
                        photos = JsonConvert.DeserializeObject<List<Photo>>(line);
                    }
                }
            }
  
            response.Close();

            return photos;
        }