Microsoft KB Archive/926964

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Error message when you use Outlook 2007 to visit SharePoint Server 2007 Web sites that are configured to use client certificate mapping: "401 Unauthorized"

Article ID: 926964

Article Last Modified on 4/25/2007


  • Microsoft Office Outlook 2007


Consider the following scenario:

  • You have several Microsoft Office SharePoint Server 2007 Web sites that are configured to use client certificate mapping.
  • You connect the Calendar list from more than one of these Web sites to Microsoft Office Outlook 2007.
  • Your user rights differ for each Web site.

In this scenario, when you use Outlook 2007 to visit one of the Web sites, you are prompted to select a certificate as expected. However, if you then visit a SharePoint Server 2007 Web site that requires a higher level of permissions, you are not prompted for a different certificate. Instead, you receive the following error message:

401 Unauthorized

You expect to be prompted to re-authenticate if your current authentication is unsuccessful.


This problem occurs because after you select a certificate in Outlook 2007, Outlook 2007 continues to use that same certificate until you restart Outlook.


To work around this problem, use one of the following methods to synchronize two or more SharePoint Server 2007 Web sites with Outlook 2007:

  • Restart Outlook 2007 after you synchronize Outlook with each Web site.
  • Use a certificate that has sufficient permissions for all the Web sites.

For example, if Site A requires that you have Contributor access, and Site B requires that you have Administrator access, use a certificate that has Administrator access. This is because the Administrator access certificate includes support for Contributor access.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

Additional query words: OL2007 Outlook2007

Keywords: kbpending kbbug kbexpertisebeginner kbtshoot kbprb KB926964