Some underlying faults might prevent you from streaming your smartphone or computer to your Fire TV. One such common problem is outdated Fire TV software.
To see if this is the cause, check to ensure your Fire TV’s operating system is up to date. You can do this by going to Fire TV Settings, then My Fire TV. If you find that it needs an update, you’ll need to update it to the latest software version.
If you’re using an HDMI cable, you also want to check if it’s in sound condition and well inserted into the appropriate port. Your laptop’s screen will also fail to mirror on your TV if you’ve switched to the wrong HDMI input on the TV. So ensure your HDMI port tallies with the HDMI input on the TV’s UI.
Additionally, switching off and on your TV works most times. Then ensure your Fire TV has an active Wi-Fi connection and uses the same Wi-Fi network as the device you want to mirror.