I have a simple web service that is in a virtual directory under a WSS 3.0 web app virtual directory. If I log on to the box and use IE to execute the web service it works. If I write a web part it fails with:

The request failed with HTTP status 401: Unauthorized

The really strange thing is that it works in production, but not the new test server! I have looked at both web.configs and IIS settings and see no differences. Both boxes are running Server08, IIS7 and WSS 3.0 (

Any ideas?

2 Answers 2


Check the loopback issue: http://support.microsoft.com/kb/896861

  • looks like you sniped me.... Jun 9, 2010 at 21:18
  • Sad thing is that I knew about this and did not check it because I thought I already had!
    – Mike Polen
    Jun 11, 2010 at 12:42

Here are some additional details that may be of value. http://www.harbar.net/archive/2009/07/02/disableloopbackcheck-amp-sharepoint-what-every-admin-and-developer-should-know.aspx

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