E16 is displayed and the machine reports a door or service panel open error even when closed.

Safety first: Unplug the machine before adjusting the door or switch.

• Open and close door: Open the service door fully and close it firmly until you hear a click. Ensure no cables or hoses obstruct closure.
• Inspect latch and tabs: Check the plastic latch and tabs on the door for cracks or wear. If broken, the door will not actuate the switch.
• Clean switch area: Use a dry brush or compressed air to remove coffee grounds or dust around the door switch.
• Test switch (advanced): With the cover removed, manually press the microswitch and see if the error clears. If not, the switch or wiring may be defective and require replacement.