Agree with others that lack of air flow is why the AMNPS went out. Also no water, foil the pan for drippings, vent wide open, no wrap, and chip loader out 1-2". I actually leave it out altogether for a while and once I am confident its running I insert and throttle it down a bit.
WRT temps, 2 butts in MES is a big job (thermal mass) and would easily take the MES a few hours to catch up. That is, assuming you had pre heated. I think this might be a factor on this smoke. I turn it on, load the AMNPS, light it, put in MES, and proceed to get meat. Temps are 275 by then. FYI when I ran 2 butts it was a 25.5hr smoke and there is a post here by a poor guy that ran 4 once and he was in the stall around 40hrs.
Hang in there, you'll get it and the results are worth the effort!
WRT temps, 2 butts in MES is a big job (thermal mass) and would easily take the MES a few hours to catch up. That is, assuming you had pre heated. I think this might be a factor on this smoke. I turn it on, load the AMNPS, light it, put in MES, and proceed to get meat. Temps are 275 by then. FYI when I ran 2 butts it was a 25.5hr smoke and there is a post here by a poor guy that ran 4 once and he was in the stall around 40hrs.
Hang in there, you'll get it and the results are worth the effort!