Your iPhone or iPad may be muted. If your device has a side switch, flip it to the "off" position to unmute it. You will know it is unmuted if you do NOT see the switch's orange line. Then, make sure the volume on your device is turned up. You should now be able to hear sound on the Nick App.On some iPads, you can go to Settings > General > Use Side Switch and change the setting to Mute. Then make sure the switch is in the off position.