I'm guessing this is a Dobot Magician robot arm?
Double check the motor connections? If only one coil is working it could get warm but not move? Also, there are two different motor pinouts with the same socket on the motor - the inner two used pins are swapped in one standard.
If there is too much grip force on the filament, the motor may stall - or if the filament has hit a step or ridge in a coupling feeding in to the hot end, that can jam it solid.
For that, try removing the filament and scrape the end to a point rather than a square cut?