If you ever configure a (domain group-) policy setting, that prevents you from administrating your server, or in my case, disables the network connections and removes the ability to refresh the domain gpo’s, you can reset the policy settings using this command:
secedit /configure /cfg %windir%\repair\secsetup.inf /db secsetup.sdb /verbose
But be aware, that running this command on a domain controller will probably reset yout gpo’s stored in active directory as well !!! Having a backup is recommended :-)