Restart Your Device and Network Connections
Try restarting your device, router and/or modem to see if this resolves the problem.
To restart your device:
Unplug the power adapter for three seconds, then plug it back in.
You can also restart your device with your remote. Press and hold the Select and Play/Pause
buttons at the same for about five seconds, until your device restarts. Or, select Settings > System >
Restart from the Fire TV menu.
To restart your router/modem:
Unplug the power adapter(s) and wait a full 30 seconds.
If you're using both a router and a modem, reconnect power to your modem first, then reconnect your
router.
Wait until both your router and modem have fully restarted before attempting to connect to your
network again.