Product:
Cognos TM1 architect 10.2.2
Microsoft Windows 2012 R2 standard server

Problem:
Login dialog when you start TM1 architect, and you have configured it to be SSO to the Cognos BI Cognos Connection.
If you surf to http://cognosBIserver.domain.com/ibmcognos you are automatically logged in.

Login dialog titled : Windows Security

tm1a.exe connecting to biservername.domain.com

User name

Password

…

Solution:
On the computer where you start TM1 architect, go to control panel and internet options.
Go to Security tab.
Select Local Intranet and click on sites button.
Click on advance button.
Enter the URL to the Cognos BI server;
http://biservername.domain.com
Click on Add button.
Click Close.
Click OK.

Restart TM1 architect, and see if the SSO are working.

For SSO to work with TM1 clients and Cognos BI the CAM authentication Bi server must be in local intranet or trusted intranet zone of Internet Explorer on client computer.