My workaround for having problems with offline use has been to get out of my work network (taking the laptop home, or going where there is just wi-fi), opening Drone2Map, and setting it up for offline use there. Then, when I am done with using it completely offline, again opening Drone2Map while off my work network but connected to wi-fi, going back to the licensing interface, and unchecking the "Authorize Drone2Map to work offline" box.