ASP.NET

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