I am currently working on a hexacopter. After completing the assembly I tried to calibrate the motors. One of the motors didn't spin properly and smoke started coming from it. This happened twice. I don't know if the problem is with the motor or the ESC. I made sure all the wires are perfectly soldered and connected. Attached sleeves as well. I am really not sure where the problem came from. Would be great if someone could tell me where I went wrong. Btw, Im using T-motor 400kv and T-motor ESC 40A.