Test data source for TM1 cube does not work

Cognos Analytics 11.0.6
Microsoft Windows 2012 R2 server

In a new setup, we created a data source to a TM1 server, but when doing test in Cognos connection we get a error.
Test of SQL server data source is working.

This is in a SSO CAM security setup with Active Directory.

Error message:
XQE-CM-0008 Unable to retrieve credentials for namespace “CAMID(“AD”)”: java.lang.NullPointerException

In some cases the test of data source does not work when using external authentication.
Set to NO AUTHENTICATION and test again.
If the test works, set it back to you AD External Namespace authentication.
Create a report and use that to test that you can get some data from the TM1 data source.

As per the IBM Cognos documentation, you are not able to test a data source which is configured to use an external namespace for authentication.