Means it's having problems connecting triangle #150 (which sits in front of one of your doors) to the door portal. If you get that warning when finalizing, there should be a 'find triangle' button (or something like that) that will take you to it. Should be able to manually drag the 3 points in that triangle so they're closer to the door, higher up off the ground/floor, and make it so it's even-sided and about the same size as the doorway is. That usually fixes it for me.