This video provides more clues as to why it went down, but it holds nothing to tell us what caused the “malfunction” in the first place.
An amateur video, run by Iranian news agencies and purportedly of the crashing plane, showed a flash in a dark sky descending rapidly with comments that the aircraft was “on fire like a fireball”, and then a brighter flash exploding/burning as it appears to hit the ground.
The Guy in the video ” He is saying the plane is burning and does some praying, is concerned. Then at the end, he says call emergency services. “
According to flight data recorded by Flightradar 24, the plane took off at 2:42 universal time, or 6.12 a.m. local time, a little more than three hours after Iran launched more than a dozen ballistic missiles at Iraqi bases hosting U.S. troops. Three minutes later, it had reached an altitude of nearly 8,000 feet and was continuing to climb at a steady ground speed of 276 knots, or 318 mph. Then, abruptly, it dropped. A state-run Iranian media outlet released a video that appeared to show the aircraft descending in flames before impacting the ground
In this video, Appears like a missile heading to its target. Notice that it appears to burn like a solid rocket fuel motor.

Notice at frame @24 seconds of the small light heading into the sky, then the burst of light, then the fireball at @30.