Diagnosis
The wireless link between the camera and monitor has been lost. This can happen after a power flicker or if they've gotten too far apart during setup.
How to Fix It
1. On the monitor, press the Menu button. 2. Use the arrow buttons to select 'Camera Pairing' and press OK. 3. You'll see a screen asking you to pair. Now, on the back of the camera, press and hold the small Pairing button (next to the power port) for 3 seconds until the light flashes. The monitor should connect within 15 seconds.
If That Didn't Work
Power cycle both units completely. Unplug both camera and monitor for 60 seconds. Plug the camera in first, wait for its light to go solid, then plug the monitor in and try the pairing process again.
Heads Up
The pairing button on the camera is tiny. Use a paperclip or pen tip. Don't hold it for more than 5 seconds, or you might trigger a factory reset.