If the bucket that you're milling the grain into is too full, crushed grain can build up inside the roller housing, causing the motor to get stuck/jammed.

If this happens:

1. Immediately turn off the mill and unplug it to protect the motor.
2. Shake the mill over a container to remove all the crushed grain that has built up in the roller housing.
3. Re-mount the mill over a bucket with adequate space and continue milling.

If the motor jams and the bucket is not full, the cause may be the mill gap setting being too small.

If this happens:

1. Turn off the mill.
2. Then increase the motor speed to 6.
3. Then increase the mill gap setting to 10.
4. Turn the mill back on and this should resume normal crushing within a few seconds.
5. Immediately, once normal crushing has resumed, reduce the mill gap setting to 1 or 2 settings higher than the setting at which the issue was experienced (eg if the motor jammed at setting 2 for this malt, crush at settings 3 or 4 instead).

If still jammed, you may need to repeat the process and further increase the mill gap setting until it starts to crush normally. 

Depending on the nature of the issue, what can also help is whether the hopper is filled before or after the mill is turned on. Feel free to try both methods and do what works best for you.