Touch panel is malfunctioning.
If the screen does not respond correctly when you touch a key (the machine does not perform the operation or performs a different operation), follow the steps below to make the proper adjustments.
Holding your finger on the screen, turn the main power switch to OFF and back to ON.
Lightly touch the center of each +, in order from 1 to 5.
Turn the main power to OFF, then turn it back to ON.