If a power reset doesn't do it, and make sure the probe/plug are clean, call Steve. He'll send you a replacement (still under warranty). Unfortunately, probes fail... that's why they only have a 90-day warranty. They are very sensitive to abuse, like being submerged in water, or dropping onto the element. Not saying that's what happened, just explaining the short warranty. You'll get another one, no problem!
If you need to smoke something by temp, just use an external thermometer, and set the controller to time, until you get your replacement.