https://www.youtube.com/watch?v=JOuEL2UhLaI
However ... and despite I can see at the end of the process the message "The NAS has joined the domain successfully.", In my scenario, after the "processing ..." pop-up I can't see AD information in the "Domain Security" window (in the QNap web interface, I mean) ... Instead the chosen option is moved automatically from "AD authentication (domain members)" to "No domain security (local users only)" ...
But I can't see something relevant in the "QuLog Center" ... In fact, the last event I can see in there is "Enabled the following domain security option: Active Directory authentication" ... Which is completely wrong" ...
Some idea on how may I diagnose what's happening? Thank you very much guys!
