HttpWebRequest "operation has timed out"

I am using an httpWebRequest in my windows app to download files from a webserver (sURL), to a local folder (fileDestination) as such:

Public Function DownloadFile(ByVal sURL As String, _
                        ByVal fileDestination As String, _
                        ByVal WebRequestType As String) As Boolean  


    Dim URLReq As HttpWebRequest
        Dim URLRes As HttpWebResponse
        Dim FileStreamer As FileStream
        Dim bBuffer(999) As Byte
        Dim iBytesRead As Integer
        Dim folderDestination As String
        Dim sChunks As Stream

        Try

            FileStreamer = New FileStream(fileDestination, FileMode.Create)

            URLReq = WebRequest.Create(sURL)
            URLRes = URLReq.GetResponse 'Error occurs here!!
            sChunks = URLReq.GetResponse.GetResponseStream
            DownloadProgressBar.Value = 0
            DownloadProgressBar.Maximum = URLRes.ContentLength

            Do
                iBytesRead = sChunks.Read(bBuffer, 0, 1000)
                FileStreamer.Write(bBuffer, 0, iBytesRead)
            Loop Until iBytesRead = 0

       开发者_高级运维     sChunks.Close()
            FileStreamer.Close()
            URLRes.Close()

            Return True
        Catch ex As Exception
            Return False
        End Try

End Function

This works fine for the first few files. But then it starts giving the following error on the URLReq.GetResponse line:

"operation has timed out"

Anyone know what could be causing this?

If you're targeting the 1.1 framework and are running multiple concurrent requests try setting System.Net.ServicePointManager.DefaultConnectionLimit

The timeout is set to 10000 milliseconds (or 10 seconds). Is that long enough for the roundtrip to the web server?

The MSDN Documentation says the default is 100 seconds (100000 ms) is there any reason you changed that default?