Check your HDMI connections
Your HDMI cable might be acting up. Disconnect it from your YouView box and TV and then reconnect it.
Still not working? Try using a different HDMI cable.
Restart your box
The old “switch it on and off” routine. Overused but it can often help resolve the issue. Press and hold the button on your box for 8 seconds, then let go. You’ll be greeted with a friendly ‘Hello’ telling you that your box has restarted.
Change the channel
Simple but effective. Try changing the channel and then going back to the original channel.