I'm sorry about the issue. What's the model of your internet modem / router device?
Can you 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?
What's the error or message when entering your new wireless / Wi-Fi password ***** your kindle?
Please type at the box below, then click on the Send button below to communicate with me, so I can help. Thank you,