This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice This article is not considered official documentation for K2 software and is provided "as is" with no warranties.


Domain users are unable to login to K2 sites using Windows Authentication. After three attempts, it leads to a 401 error.


Domain users who do not have administrator rights on the web server where the K2 site is hosted get this issue.

Troubleshooting Steps

Please check the following items:
  1. A single provider is enabled.
  2. The application pool account is not a system account.
  3. The application pool account is a member of the IIS_IUSRS Group. 
  4. The IIS_IUSRS group has Modify rights to the Windows\Temp directory.
  5. The following policies are granted to the Authenticated and Domain users on the web server:
    Access this computer from the network
    Log on as a batch
  6. The K2 Site URL is added in either Local Intranet or Trusted Sites under the Internet Options in IE.