MS Win 10 (x64): no energy saver after domain login

Hello everyone!

I have a Mac Mini (end 2014) with OS X El Captain and MS Win 10 (x64) on BootCamp: it's in a Active Directory domain.

When I switch on the Mac, if I DON'T logon in that case the Mac goes in Energy Saver status (the monitor switch off and the Mac's led light flashes).

Otherwise if I insert my domain username and password and I logon into domain in that case the Energy Saver doesn't function: the monitor and the Mac are always switch on.

The monitor is connected through HDMI port.

Any ideas to solve this problem?

Thank you very much.

Best regards.

Alessandro