Disable ASP.NET Impersonation
1. Open Internet Information Services (IIS) Manager
2. Navigate to to Sites > Default web site > QuestKnowledgePortal > Authentication
3. Right-click and disable ASP.Net Impersonation
4. Navigate to Application pools > right click on Quest Knowledge Portal 2.11 Application Pool > Advanced Settings
5. Under Process Model > Select Identity > Click on "Options(...)"
6. Select either "Built-in Account as Local System" or provide details of a custom account.
7. Restart the IIS Services and test setting security again in Knowledge Portal (Close and re-open the browser first).