Whats the domain box on the logon page for ?
At first I thought that it might be for active directory authentication (that would be cool) but it doesnt appear to be and theres no settings relating to domain in the logon prefs in system.
You are correct. If you run a LAN watch on a domain controller then click View AD Users under the Agent tab, you'll see the discovered users and can either create Kasyea administrators or Kaseya 'users' which allow access to ticketing.
to extend on Ben's remark, if you create an AD User as he recommends, it's a full VSA that "Does" auth to their AD. so you don't have to worry about passwords, it'll follow their AD rules and match their profile password and username. I recommend if you're setting up your Tech's with AD Users in Kaseya (DONT). It works great for customers, but for you it's a bad idea. If ever your AD is down or unaccessible you can't login to your kaseya VSA. Our building does regular maintenance on their power, so our AD is off-line on some weekends.
Just a HEAD's UP :D Cheers!!!!