I'm sorry about the issue. Can you please press and hold the Power on / off button on your Kindle Fire for about 30 seconds, then turn it back on and check?
Please reply at the box below to continue. Thank you,
If the above suggestion still does not let you turn on Wi-Fi or connect to Wi-Fi, please go to menu / settings on the kindle, then go to the option Device (or Device options), then option Reset to Factory Default, then confirm Yes / Reset, and continue.
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,