Sounds like the propane is not igniting so in a couple of minutes the fan shuts off. So it is not getting propane or spark. You might have been able to hear the tick, tick, tick of the spark. I never read about smelling any propane.
In a nearly new unit, I would guess Chris is right, the sail switch is not responding to the fan and approving the propane delivery from the gas valve to the burner.
The tech should have you back in operation in no time.
As a note: I have added a T fitting and shut off valve into my furnace gas line for a ventless heater. Saves noise and propane. Before anybody starts spanking me, I have the proper safety equipment on the heater and in my rig monitoring the oxygen. Plus, I am quite certain my rv has many air leaks for replenishing oxygen and I monitor condensation levels. That said, I feel perfectly safe and warm in my rig.