If you can see the games on your TV but cannot hear any sound from the TV's built-in speakers after setting up Nex Playground, please try a few things:
Make sure you have adjusted the volume using your TV remote and your TV isn't on mute.
Go into your TV's audio settings and make sure the Audio Out settings is set to TV speakers.
Try rebooting your Playground by unplugging the power cable for 10 seconds.
If Playground is connected to your TV via another device (e.g. a receiver), please try a direct connection.
Try a different HDMI input.
Try a different HDMI cable.
Try connect Playground to a different TV or monitor, some monitors have HDMI input.
Tips: Certain Vizio TV models intermittently lose audio on HDMI inputs, some users have successfully worked around such issue by pressing the WatchFree (or WatchFree+) button on the Vizio remote and wait until a channel starts playing with sound. Once audio is confirmed there, press Input and switch back to the HDMI source used by Nex Playground.