Was trying to do the 125% test on a mono 500; loaded the car up, inhibited doors and calls, then sent it to run one floor down to verify the elevator could handle the weight at contract and leveling speed. It got up to contract speed fine, but when trying to level into third floor it stopped. Attempted to run it down on MR to get it into the floor; but after a few failed attempts to get it to move it stopped trying to turn, even with a drive down command hi. Drive need is hi, drive ok is intermittent, elevator is lost and trying to sync.

Any idea what I did wrong and how to fix it?