Black Mana Studios

Red box - illegal room, usually means some of the corner points of that room are crossed. To solve it, simply zoom in on the plan (in layout screen), select the room and make sure the points do not cross each other and are snapped all the way to the adjacent room. If that doesn't work for you, you can send your plan to support@blackmana.com and one of our agents will fix the plan for you and send it back.