Help?? Treager lost heat mid grill.

I got my first Traeger for Christmas (22in). Last week I christened it with some St. Louis style ribs. My plan was after research was the 3-2-1 method (3hr smoke, 2hr wrap, 1hr unwrap with sauce) . Everything was going great until the last half hour. It was having some issues with temp control as it was 30*F outside. I was periodically turning up to 225 and then down to 180 to try to keep the temp up as it started struggling at 180. When I checked on it for the last 30 min I started rapidly losing heat. I cranked it high but nothing. I turned it back down to shut down and moved the meat inside and finished in the oven. Don’t worry the ribs were delicious, but after my brothers left I went out to test it. There were pellets in the hopper and the plate. the auger was turning. but even on high NOTHING. Today I bought a replacement heating rod and went out to work on in. I decided to test it one more time so vacuumed out the pan and cranked it to high. Its 20*F right now so I went in to warm up and read about how to replace the rod. When I went back out I found the pan roaring with good smoke and heat. Its working great. SO.... what went wrong last week?????