Receive 401 from Stream api


All of a sudden I receive a 401 Unauthorized error when trying to access the Twitter Stream API. It was working 3 days ago but not since yesterday. I have tried with two different accounts and even to connect from different IP:s.
Here is my code in VB.NET that always been working, but not now since yesterday :

Dim url As String = ""
Dim request As WebRequest = WebRequest.Create(url)
request.Credentials = New NetworkCredential(“XXXXX”, “XXXXX”)
Dim WebResponse = request.GetResponse()

    Dim responseStream = New StreamReader(WebResponse.GetResponseStream(), encode)

I am very thankful for any help!