Windows user failed to authenticate on Web Server RRS feed

  • Question

  • Hi,

    I have three tier deployment for sharepoint and I am using claim based authentication.

    When I tried to login to SharePoint using windows authentication on web server it's saying unauthroize.

    But same thing when I tried from application server it's working fine.

    I have add the domain user as farm administrator and has full control

    Don't know what's happing wrong with it.



    Thursday, March 15, 2012 6:00 AM


All replies

  • Hi Pramod,

    If you got as the following error:
    ProtocolError occured trying to complete the request. The server returned a status code of : ProxyAuthenticationRequired and the status description is : "Proxy Authentication Required ( Forefront TMG requires authorization to fulfill the request. Access to the Web Proxy filter is denied. )"


    There are two things you can do, but maybe just one will work. In my case, solution 2 was in the end the only solution after testing and investigating half a day.

    Solution 1

    1. Navigate to the virtual directory of the SharePoint site, like: C:\inetpub\wwwroot\wss\VirtualDirectories\yoursitename

    2. In the root you will find the file web.config. Edit this file and search for the line with <system.net>. Now copy and paste the following lines and make sure you change the value proxyaddress to the address of your own proxy server:

        <defaultProxy enabled="true" useDefaultCredentials="true">
            <proxy bypassonlocal="true" proxyaddress= />
    3. Save the file and restart IIS. To reset IIS, click Start > All Programs > Accessories > right-click Command Prompt, select Run as administrator, type in iisreset, and press ENTER.

    Solution 2

    Configure ISA/TMG to allow unauthenticated traffic to the Internet. Just add a rule which allows the SharePoint frontend server to navigate to the Internet (network External) over port 80.  Rule settings:

    Action: Allow

    Protocols: HTTP (80)

    From / Listener: hostname of your frontend server

    To: External (Internet)

    For more information, please refer to the following link(SharePoint 2010):

    Lhan Han

    Monday, March 26, 2012 9:11 AM
  • Hi Lhan,

    I got the solution and windows authenticaion is working now.

    I refer following KB which suggest to change some registry value.




    • Marked as answer by Pramod S Monday, March 26, 2012 2:13 PM
    Monday, March 26, 2012 2:13 PM