Error: Security settings for this service require Windows Authentication but it is not enabled for the IIS application that hosts this service.

Q. I'm getting the following error when I test Silverlight services for my EP configured to use Windows authentication by entering http://myEPsite/Services/UserService.svc address as per this article.
Neither Interactive Gantt nor Activities (Silverlight) pages are loaded.

Security settings for this service require Windows Authentication but it is not enabled for the IIS application that hosts this service.


A.
If this error is returned and Windows Authentication has been enabled in IIS, it means there is an issue with the supported network authentication schemes for the website that the web service is installed under. The most likely cause is that it is configured for NTLM only while it should use both NTLM and Negotiate.

The following Microsoft KB article describes how to enable both schemes:
http://support.microsoft.com/kb/215383

After this has been done IIS will need to be restarted, or EP application will need restarting (load the Web.Config file and save without changing anything).

Article ID: 145, Created On: 4/12/2011, Modified: 11/3/2011