I'm sorry about the issue. Please press and hold (or slide and hold) the power on / off button / switch on your kindle for about 45 seconds, then turn it back on and check.
Please reply at the box below to continue. Thank you,
If there is still any issue, please let me know the model of your kindle.
When you are available, please type at the box below, then click on the Send button below to communicate with me, so I can help further. Thank you,