[Woodworker]

The gas isn't reaching the furnace. Might need to light the stove for a few minutes and it will draw the gas in. I actually had a similar problem yesterday morning, the fan came on, then the furnace lit for about 5 seconds then went off. Turns out one propane tank was empty and the other didn't have enough propane to create pressure to keep the furnace lit. If your rig is a 2019, it still has warranty, call your dealer, he probably has a quick fix. Good luck.