Step 1) Make sure the TV screen has the correct input source (HDMI, VGA or PC).
Step 2) Make sure there is no technical work taking place or any issues with your network, in that case please contact your IT.
Step 3) Reboot the media device manually from the power button (If the device has a high temperature leave the device off for 10 minutes).
Step 4) Make sure all the cables are connected to the media device.
Step 5) Make sure the TV Screen is able to produce any sound in general.
Replacing the audio cable usually resolves this issue.