Special care must be taken when using an Active Directory system and the Active Directory DNS service is the central resolution point for your internal web services.
On the left menu, choose DNS > “DNS Forwarders”
Set the local domain in the “Domain” field and the IP address of the local DNS service.
Click on Add button
Your forward rules will be added at the first place of the Local DNS cache settings.
Click on “Reconfigure service” button in order to apply the configuration in production mode.