larger file uploading issue

[silentspeaker]

I want to upload larger file but getting error:

Network Error (tcp_error)

A communication error occurred: ""
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.

Sub UploadFile()

    Try
        Dim fileName As String = FulFile.PostedFile.FileName
        Dim requestFTP As WebRequest = WebRequest.Create("ftp:....................../" & fileName)
        requestFTP.Credentials = New NetworkCredential("User ID", "Password")
        requestFTP.Method = WebRequestMethods.Ftp.UploadFile

        Dim bufferLength As Integer = 2048
        Dim buffer As Byte() = New Byte(bufferLength - 1) {}

        Dim uploadStream As Stream = requestFTP.GetRequestStream()
        Dim contentLength As Integer = FulFile.PostedFile.InputStream.Read(buffer, 0, bufferLength)

        While contentLength <> 0
            uploadStream.Write(buffer, 0, contentLength)
            contentLength = FulFile.PostedFile.InputStream.Read(buffer, 0, bufferLength)
        End While
        FulFile.PostedFile.InputStream.Close()
        requestFTP = Nothing

        LblMsg.Text = "File Uploading Is SuccessFull..."

    Catch ep As Exception
        LblMsg.Text = ep.Message
    End Try

End Sub