Fix it in this order
1
Check the connection
Open SettingsNetwork and press Play/Pause to run the network status tool. It tells you whether the Fire TV reaches your router, and whether the router reaches the internet.
2
Restart the stick and the router
Unplug the Fire TV for 10 seconds and plug it back in. Restart your router too, especially if other devices are slow.
3
Turn Wi-Fi off and on, then rejoin
In SettingsNetwork, turn Wi-Fi off and back on. If that fails, highlight your network, press Menu to forget it, and join it again with the password.
4
Improve the signal
Use the HDMI extender, connect to the 5 GHz network, or use a cable with Amazon’s Ethernet adapter. See Firestick keeps disconnecting from Wi-Fi.
5
Check for an update
Once connected, go to SettingsMy Fire TVAbout and select Check for System Update. See update a Firestick.
If the internet is fine everywhere else
- Wait a few minutes and try again. If every other device is online and the network tool shows the Fire TV connected, the problem may be on Amazon’s side for a short time.
- Check the router isn’t blocking the stick, for example with parental controls, a device block list or a DNS filter.
- Turn off any VPN on the stick or router while you test. See VPN on a Firestick.