I dont have a traeger, but a fair amount of knowledge of the pellet cookers. THe glow plug that starts the pellets might be broken. I use a Benzomatic torch to light them. See if that gets it lit and if it stays lit.
On my FEC you have a fan blade that only moves when the augur is turning. There is a seperate computer style fan that is there to keep the fire going. If those are working I am better the glow plug thing is broken.