407 authentication error VB.net while reaching https site to get the resource

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VB

errors

Dim client As HttpWebRequest = CType(HttpWebRequest.Create(url), HttpWebRequest)

Dim wproxy As IWebProxy = WebRequest.GetSystemWebProxy


If (wproxy IsNot Nothing) Then
Dim myProxy As New WebProxy()
Dim newUri As New Uri(url)
myProxy.Address = newUri
myProxy.Credentials = New NetworkCredential("un", "pwd", "dom")
client.Proxy = wproxy
myProxy.Credentials = New NetworkCredential("un", "pwd", "dom")
Else
Console.WriteLine("Proxy is null; no proxy will be used")
End If

when running in the proxy environment i am get 407 authentication error... any suggestion. i haven't messed with .app config either. Do i have to make some changes to .app config file.
my config looks like this

<configuration>
<system.diagnostics>
<sources>
<!-- This section defines the logging configuration for My.Application.Log -->

<listeners> <add name="FileLog">
<!-- Uncomment the below section to write to the Application Event Log -->
<!--<add name="EventLog">-->


<switches>
<add name="DefaultSwitch" value="Information">

<sharedlisteners>
<add name="FileLog">
type="Microsoft.VisualBasic.Logging.FileLogTraceListener, Microsoft.VisualBasic, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL"
initializeData="FileLogWriter"/>
<!-- Uncomment the below section and replace APPLICATION_NAME with the name of your application to write to the Application Event Log -->
<!--<add name="EventLog" type="System.Diagnostics.EventLogTraceListener" initializedata="APPLICATION_NAME"> -->




Thanks in advance