If there is no other solution reported for this problem you can always rest the unit.
NOTE!! This will make all settings go away!
Turn off printer
Press and your whole thumb and cover the bottom left corner of the touchscreen
Keep the thumb on the touchscreen and turn on the printer.
(It is a little tricky but leave it there for several seconds and make sure it's the whole thumb.)
Be sure and leave it there for several seconds - when the permanent storage init. message appear, release thumb -
when printer finished NVRAM, it will come to ready status