Diagnosis
This is typically a wireless interference issue. The 2.4GHz band the monitor uses is crowded with Wi-Fi routers, other monitors, and smart home devices.
How to Fix It
First, power cycle both units. Turn off the parent unit and unplug the camera from power for 30 seconds. Plug the camera back in, wait for its light to settle, then turn the parent unit back on. This often clears temporary interference.
If That Didn't Work
You need to change the camera's channel. On the parent unit, press Menu, find the channel selection option (often under a wireless icon), and cycle to a different channel (like Channel 1, 2, or 3). Wait a moment for the video to reconnect. This finds a clearer signal path.
Heads Up
Keep the camera and parent unit away from other electronics, especially Wi-Fi routers, cordless phone bases, and microwaves. Physical obstructions like mirrors, fish tanks, or thick walls can also cause this.