[Samba] Doubt about Unix Attributes

[Marcio Demetrio Bacci]

I can configure UidNumer and gidNumber attributes by Microsoft RSAT tool
and the value is stored. When I click again on the tab "Unix Attributes"
appears a message saying "Not is possible the execution". I click OK button
and  the attribute  is correct.

Why appear this message?

How can I verify if the NIS service is working correctly?

Regards,

Márcio