I have an alt account (for a holy symbol mule) but I can't log in. I get the "User ID already logged in or server is under inspection" dialog box but I've shut down all computers that I play Royals on. The server is up at this time of posting, so I don't see what the issue is (other than I got hacked).
Go to the main page of the site, http://royals.ms/?page=index, sign into the control panel with your character's login details and click on "Character Fix"