C# winfrom上传图片到ftp空间报错，100分求解决，急。。。

Question

报错内容：System.Net.WebException:基础链接已关闭，接收时发生错误
我在测试时候用自己的ftp空间时没有任何错误，能够上传的ftp的指定目录，可是换了客户的空间就报错了，请高手帮助解决，或者是给我提供一个更好的代码，谢谢大家了！
         
//这是我写的上传的方法//调用：UploadFun(filepath1, @"ftp://www.beigou.org/wwwroot/proimg/123.jpg);        /// <summary>
        /// 将图片上传到ftp空间
        /// </summary>
        /// <param name="fileName">本地图片的路径</param>
        /// <param name="uploadUrl">ftp实际路径格式：ftp://+域名+/文件夹+123.jpg</param>
        /// <returns></returns>
        private FtpStatusCode UploadFun(string fileName, string uploadUrl)
        {
            try
            {
                Stream requestStream = null;
                FileStream fileStream = null;
                FtpWebResponse uploadResponse = null;
                try
                {
                    FtpWebRequest uploadRequest =
                    (FtpWebRequest)WebRequest.Create(uploadUrl);
                    uploadRequest.Method = WebRequestMethods.Ftp.UploadFile;
                    uploadRequest.Proxy = null;
                    NetworkCredential nc = new NetworkCredential();
                    nc.UserName = "woeret";    //ftp用户名
                    nc.Password = "此处略去";       //ftp密码
                    uploadRequest.Credentials = nc; //修改getCredential();错误2
                    requestStream = uploadRequest.GetRequestStream();
                    fileStream = File.Open(fileName, FileMode.Open);
                    byte[] buffer = new byte[1024];
                    int bytesRead;
                    while (true)
                    {
                        bytesRead = fileStream.Read(buffer, 0, buffer.Length);
                        if (bytesRead == 0)
                            break;
                        requestStream.Write(buffer, 0, bytesRead);
                    }
                    requestStream.Close();
                    
                    uploadResponse = (FtpWebResponse)uploadRequest.GetResponse();
                    return uploadResponse.StatusCode;                }
                catch (UriFormatException ex)
                {
                    MessageBox.Show(ex.ToString());
                }
                catch (IOException ex)
                {
                    MessageBox.Show(ex.ToString());
                }
                catch (WebException ex)
                {
                    MessageBox.Show(ex.ToString());
                }
                finally
                {
                    if (uploadResponse != null)
                        uploadResponse.Close();
                    if (fileStream != null)
                        fileStream.Close();
                    if (requestStream != null)
                        requestStream.Close();
                }
            }
            catch
            {
                MessageBox.Show("将图片上传至服务器时出错，请稍后再试！");
            }
            return FtpStatusCode.Undefined;
        }