Display shows “Error 21”; machine may not detect the drip tray or waste container correctly.

Safety first: Unplug the machine before cleaning internal contacts.

Step 1 – Clean tray and contacts:

• Remove the drip tray and grounds container.
• Clean all metal contacts or sensor surfaces with a damp cloth, then dry thoroughly.
• Clean the corresponding contacts inside the machine.

Step 2 – Check insertion:

• Reinsert the tray and container firmly until they click into place.
• Ensure no foreign objects are preventing full insertion.

Step 3 – Test operation:

• Plug the machine back in and power on; see if the error clears.

Step 4 – Advanced sensor check:

• With the housing removed (unplug first), locate the tray/grounds container microswitch or sensor.
• Check for broken actuators or misalignment.
• Test the switch with a multimeter for proper operation.

Step 5 – Replace faulty parts:

• Replace a defective microswitch or sensor.
• If the tray itself is damaged and not engaging the switch, replace the drip tray/grounds container assembly.