Try using your remote between each step.
1. Replace the batteries in your remote. For optimal performance, we recommend using alkaline batteries.
2. Move your remote closer to your Fire TV device, within 10 feet (3 m).
3. Restart your Fire TV by unplugging the device or accessing Settings. Once you're on the home screen, press and hold the Home button on your remote for 10 seconds.
4. If you have seven controllers paired, remove one of them before attempting to pair another.
5. Use the Fire TV app to pair your remote. Download the Fire TV app on your mobile device and follow the steps in 'Using the Fire TV App to Pair Your Remote.'
6. If you're still experiencing issues, reset your Fire TV Remote and then try pairing it again.