Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble.
This symptom can indicate several possible issues: an internal hardware failure, a low/faulty battery, or just a simple memory/firmware glitch.
The first step here will be to attempt to reboot the kindle. This is done by pressing/sliding and holding the power button for 20+ seconds, or until the screen flashes (usually with an image of a tree), then release. Give the kindle about a minute to start back up, and let me know if the problem persists, we can then try some further steps.
If it continues with the same message here though, then you had most likely had a prior amazon prime or amazon kindle unlimited library subscription which has expired. Those loaned/free books may still show up in your library, but would not be accessible to you unless you have an active subscription/account still.