When this error occurs you need to calibrate the scanner.

To do so:

• Place the scanner on a clean, white A3 sheet of paper on a flat surface in ambient light.
• Power on the scanner.
• While pressing and holding the Up/DPI and the JPG/PDF/Multi-PDF/Down buttons simultaneously, press the Scan/Power/Enter button for 3 seconds. Release the Scan/Power/Enter button, and then the UP/DPI and the JPG/PDF/Multi-PDF/Down buttons.
• 1111 appears on the display.
• Do not move the scanner and wait for about 1 minute until 2222 is displayed.
• When 2222 appears on the display, press the Scan/Power/Enter button.
• Slide the scanner slowly up and down over the paper until 3333 appears on the display.
• Continue sliding the scanner over the paper until the scanner is powered off.
• The calibration has been successfully performed.