The documentation portal is undergoing maintenance. During this period, you can't create any new user credentials. If you do, you'll need to recreate the user credential after the maintenance period ends.
Effective in version 10.2 HotFix 2, you can configure an Informatica domain to use Kerberos cross realm authentication. Kerberos cross realm authentication enables Informatica clients that belong to one Kerberos realm to authenticate with nodes and application services that belong to another Kerberos realm.