Was the temperature in the low; mid; or high 20's? This is just a reference point. Five degrees either way, can make a big difference in the cabinet temperatures.
Did you check to see if the element was glowing? Although if you got up to 190°F, the heating element should have been working.
What was your vent opening? If you had it wide open, try adjusting it to 3/4 to 1/2 openings. After making an adjustment, wait a few minutes to see if the temperature drops or rises. If it rises as you decrease the vent opening, then leave it in that spot. If it lowers as you decrease the opening, then go back to your original setting, and if your original setting was less than wide opened, open it further.
How frequently did you open the door? On cold days, opening the door to check on things has even more of an effect on cabinet temperatures, and recovery times. Many place a foil wrapped brick, or some other type of heat sink in smoker to improve recovery times, after the door has been opened. Some start with hot water in the bowl, to give the cabinet temperatures a "jump" start.
What was the cabinet temperature when you first put the ribs in the smoker? When preheating, I like to get the cabinet temperatures at least 10 degrees higher than I plan to cook at. Also leaving the bisquette burner on the full time, adds a little additional heat.
When the ambient temperature is in the mid-20's; with a single element I'm able to obtain temperatures in the low 200's, though it take a longer time to get up to those temperatures, and the recovery times also take longer. I don't expect the smoker to perform like it does when the ambient temperature is higher, so I will modify how I use the smoker. I do cut down on the amount of food I will smoke/cook at one time. Three racks of ribs may be too large of a load. I would cut back to two racks. The preheat times are much longer. So I factor in a much longer preheat time. If it took about one hour to get to 155°F during the preheat time, I would say that is about normal.