I wrote a windows service a few months ago that would ping a Sharepoint list using \_vti\_bin/lists.asmx function GetListItemChanges. It was working fine until a few weeks ago when my company upgraded our Sharepoint instance to SP1.  

Now whenever my service attempts to access Sharepoint I receive an 401.1 authentication error:

Error:

> 
> You are not authorized to view this page   
>  You do not have permission to
>  view this directory or page using the credentials that you supplied.   
> Please
>  try the following: Contact the Web
>  site administrator if you believe you
>  should be able to view this directory
>  or page.   
> HTTP Error 401.1 -
>  Unauthorized: Access is denied due to
>  invalid credentials.   
> Internet
>  Information Services (IIS)
> 
> 
> 

I have checked and my privileges on the site have not changed. here is the code In which I call the list:

```
Lists listsService = new Lists();
listsService.Credentials = new NetworkCredential("UserName", "Password", "domain");
Result = listsService.GetListItemChanges("List name", null, dTime.ToString(), null);

```

It has also been brought to my attention that basic authentication may have been disabled on our farm. I don't believe I'm using that but I may be mistaken.