The "(Z) Open Front Cover and remove the paper." error message appears when a paper misfeed occurs inside the paper transfer unit.
Pull the front cover open lever, and then open the front cover with both hands carefully.
Carefully remove jammed paper under the paper transfer unit.
If you cannot pull out the paper, remove it by turning the knob on the right end of the paper transfer unit as shown in the illustration below:
If paper is jammed in the upper side of the transfer unit, pull it upward.
Close the front cover with both hands carefully.
When closing the front cover, push the upper side of the cover firmly. After closing the cover, check that the error has cleared.