First ensure that there is nothing plugged into the headphone port as that will disable the devices built-in speaker. Then test is to make sure your Amazon Fire is not muted. You can do this by simply pressing the audio buttons on the top of the device. If your device is not responding to the volume button presses and is stuck on a volume setting, there may be an issue with the buttons themselves and they need to be replaced. Finally, If the Amazon Fire responds to the button presses and displays the volume level changes and still produces no sound coming from the outer speaker, your speaker itself may be faulty and needs to be replaced. For more information regarding troubleshooting your Amazon Fire 5th generation, click here.