I have installed a fresh Umbraco 4.0.3 on the Production Server, and created a new website ...etc.

I wanted to enable Integrated Windows Authentication and removed Anonymous Access from IIS Directory Security Settings for the sake of testing.

As soon as I browse Umbraco website, I get a prompt to login, and no matter what I do, it does not work.

I get this error under IE:

You are not authorized to view this page

I was really surprized, beucase it was working fine on the Development Machine !!!! I compared all setting between DEV and PROD and everything seem correct.

After googling around, I found the solutuion.

To solve the error, you have to edit the MetaBase.xml file in "%systemroot%\system32\inetsrv" on the server and add this property:

NTAuthenticationProviders="NTLM"

... in the <IISWebServer> section of the Umbraco website "MyWebSite" under IIS. It should look similar to the following:

<IIsWebServer Location ="/LM/W3SVC/1288021755"
  AuthFlags="0"
  LogPluginClsid="{FF160663-DE82-11CF-BC0A-00AA006111E0}"
  NTAuthenticationProviders="NTLM"
  ServerAutoStart="TRUE"
  ServerBindings=":80:MyWebSite"
  ServerComment="MyWebSite"
 >
</IIsWebServer>

I hope this will be of help to you, in case you face similar problem.

Tarek.