There are a few things that you need to check, first is the heat element glowing red in the back of the unit, and secondly is your “V” shaped drip tray in like a “V”?
How much meat do you have in the unit? Is there space between the meat for air flow? Did you preheat your smoker? This should be done for 30-60 min, your meat should be at room temperature when it enters the smoker, Make sure you are not using foil, and lastly, make sure that the damper is open at the top of the unit.