My wife and I were sitting on the patio while I was smoking some beef back ribs. I was watching the app and all was going well. All of a sudden the actual temp started going down from 225 to 200 to 160, when all of a sudden the grill went kaboom puff, and started smoking heavily. I unplugged the grill, opened the hopper to make sure I didn't have a fire there. It's still smoking like crazy. What should I do? What should I look for?