Stepper motors can Confuse the makers to extreme. when they only run in one direction
even when they have to do the counter of the first.
It usualy happens when a 6 wire stepper is integrated with a 4 wire driver.
eZ way out. short the pair of the stepper , and if the rotational resistance of the shaft /spindle increases
dramatically . the pair selected is the right pair 2/6 gone right
do it again with the remaining out of 4 and two of them will be a perfect match
at this stage 4 / 6 have been selected which will match the driver connections
2/6 have no use in this setup , so they can be hanging loose or un connected
The question is What help do you need On motors: