First make sure that the Vacuum switch symbol and the lid switch symbol on your screen stay on at all times. If any of those two symbols go off, the pellet stove will stop feeding and consequently the fire will  go out. If one of theses switches go off, check those switches and connections ( vacuum switch is located on the left side, take rear left panel off through the wing nuts that are located in the hopper to the left ), lid switch is right by the lid ( you may have to bend the arm for adjustment ). If that checks out, then look at the closing thermostats located on the exhaust fan housing ( take right rear panel off for that ). There are two stats, one is a spare, check for good connection or replace the  thermostat. Order TS1902. Keep the spare away from housing / heat.