AAA-AUT-0011 Invalid namespace was selected

I’ve implemented a single signon functionality for COGNOS 10.

Click on a link from one of our internal web site will authenticate users and log them into Cognos. And once they are logged in, and if a user closes the browser tab/window of the cognos web site and again click on the single signon link, I’m getting “AAA-AUT-0011 Invalid namespace was selected.” error.

I’m basically new to Cognos so any help regarding this issue is very much appreciated.

Need more info.
Active Directory?

Attach your cogstartup.xml.

I see “localhost” in your screenshot. NEVER EVER use localhost. At the very least use a server name, but Fully Qualified Domain Name (or IP) is better/recommended.