DIAGNOSIS Moisture, steam, or coffee splatter has likely gotten behind the screen's bezel or the capacitive touch layer is failing. It's a known weak point on this model.
FIX First, try a full power cycle. Turn the machine off at the side switch, unplug it from the wall, and leave it for a full hour. This can sometimes reset the touch controller. Once powered back on, use a microfiber cloth and a tiny amount of isopropyl alcohol (<70%) to meticulously clean the screen and the area around it, ensuring it's completely dry.
IF THAT DIDN'T WORK If specific areas remain dead or it's still acting up, the touch digitizer is probably faulty. There is no user calibration or reset for it. The entire front panel assembly would need replacement, which is a warranty or paid repair job.
HEADS UP Be aggressive about wiping steam and splatter off the control panel immediately after use. Prevention is the only real fix here.