I am trying to use ADS for authentication and i have strange problems.

It works fine for a few days and then it stopped working and has connection problems.

So first i have questions to solve maybe my problems:

I found this in the Open-E Knowledgebase:

There are no special settings you need to do. You need to sync with the ADS using Open-E GUI (Configuration->NAS resources) and chose the ADS option. Then, enter the realm (Domain+user) KDC IP and administrative account username and password.

I don't understand the realm definition. Domain+user???? Which user? Can someone show me an example?
Our realm is "ims.ea". I think ....

In my logs i found this:

kerberos_kinit_password ULTRIX$@IMS.EA failed: Preauthentication failed

It is correct to disable kerberos preauthentication on ADS server side for my administrative user (only)???

But my main problem is this:

Database is empty or connection error!

I see this when i am trying to start or restart the authentication method. It was working several days fine and now it does not work again ....