You can solve most intermittent issues by restarting your Fire TV Cube in one of two ways. Unplug your device and plug it back in. Alternatively, press and hold your remote’s Select and Play/Pause buttons for five seconds. If the issue persists, make sure that you’re following these recommendations:. Use the power adapter that came with your device. Use a high speed HDMI cable verify that your TV is on and set to the correct HDMI input channel. Make sure that connected devices (like an A/V receiver or sound bar) are turned on.