DIAGNOSIS The printer's main logic board or touch panel controller has locked up. A full power cycle is required to clear the state.
FIX Press and hold the printer's Power button for at least 10 seconds. The display may go blank. Release the button. Unplug the power cord from the rear of the printer. Wait for two full minutes. Plug the cord back in and press the Power button to turn it on normally.
IF THAT DIDN'T WORK Perform a factory reset. With the printer on, press and hold the Stop button and the Power button simultaneously. Hold for 10-15 seconds until the screen changes. Release and use the hardware buttons (if functional) to navigate and confirm the reset.
HEADS UP A persistent unresponsive screen often indicates a failing control panel assembly. If the reset does not work, the hardware likely needs replacement.