Open Doors Table 53. Open doors in the stapler/stacker EN 3,000-sheet stapler/stacker troubleshooting 495 Control panel messages Event log error message User LED Service LED Description Recommended action Stkr: Attach to printer N/A Blinking amber Blinking green The device is detached from the printer. Attach the device to the printer and verify that the user LED is green. Stkr: Close stapler door N/A Blinking amber Blinking green The stapler door is open. Close the stapler door.