FTP file upload on Local Network C#

Question

I have a problem while uploading a file in FTP server. When i run FileZilla server on my computer(127.0.0.1), the image files are succesfully uploaded. But i run FileZilla server on another computer in the same network.(10.0.1.25). I can create directories on this computer but i cannot upload the image file although my user have full control on this computer.

 public bool Upload(Stream srcStream, string dstFilePath)
    {
         Create FtpWebRequest object from the Uri provided
        FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(serverUri + dstFilePath));
        reqFTP.Credentials = credential;
        reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
        reqFTP.UseBinary = true;
        reqFTP.Proxy = null;
        reqFTP.UsePassive = false;
        reqFTP.KeepAlive = false;
        reqFTP.ContentLength = srcStream.Length;
        byte[] buff = new byte[UPLOAD_DOWNLOAD_BUFFER_SIZE];
        int contentLen;

        // Stream to which the file to be upload is written

            using (Stream dstStream = reqFTP.GetRequestStream())
            {
                // Read from the file stream 2kb at a time
                contentLen = srcStream.Read(buff, 0, UPLOAD_DOWNLOAD_BUFFER_SIZE);

                // Till Stream content ends
                while (contentLen != 0)
                {
                    // Write Content from the file stream to the FTP Upload Stream
                    dstStream.Write(buff, 0, contentLen);
                    contentLen = srcStream.Read(buff, 0, UPLOAD_DOWNLOAD_BUFFER_SIZE);
                }

                dstStream.Close();
            }
        }

        // Get the response to the upload request.
        bool ret;
        FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
        // ret = (response.StatusCode == FtpStatusCode.ClosingData);    // 
        response.Close();

        ret = (GetFileSize(dstFilePath) == srcStream.Length);

        return ret;
    }

When i change the line 9 to reqFTP.UsePassive = true, the server returns the (227 Entering Passive Mode (h1,h2,h3,h4,p1,p2)). Now it returns (500) Syntax error, command unrecognized. What will the problem? Thanks

Answer 1

I can upload image Filezilla while antivirus is running. However when i try it by using my code block. It returns port error message. After antivirus is stopped, everything works well.