If this error message appears on a Kindle, follow the steps below from the Amazon site:
Unplug the Kindle if it is charging
Perform a hard reboot by pressing and holding the power button at the bottom edge of the device for 40 seconds (counting slowly) and then releasing it.
Do not press any other buttons or interact with the touch screen while the device reboots. It may take a few minutes for the books to reappear.
If the Kindle is still unresponsive, please email us and return the Kindle to the Ford Library circulation desk during the business day (M-F, 8am - 6pm).
