Hi @Anonymous User
Do you mean your TV is showing a blank screen with a no signal message or if you are using a nowtv smart Freeview box you have lost the live Freeview TV channels.
With the former, try rebooting the nowtv box by temporary disconnecting the power to the box for about 30 secs.
If that doesn't work, power down both the TV and box and disconnect and reconnect the HDMI cable both ends between the box and TV.
Should the above not work, try a different HDMI port and another HDMI cable to see if that fixes it.
