For a trust relationship to work, your realm must be able to communicate with the trusted realm. You can verify communication between realms by testing the trusted realm.
Before you begin
Perform this test after you have added the trusted realm, or any time that cross-realm authentication continually fails. For more information, see Add a Trusted Realm.
In the Security Console, click Administration > Trusted Realms > Manage Existing.
Select the trusted realm that you want to test.
From the context menu, click Test Trusted Realm.
A message indicates whether the test succeeded or failed. If the test fails, try reimporting the trust package that you received from the trusted realm.