ADT Outdoor Camera has power or battery problems

The checks in more detail

If the LED is dark, check the outlet with another device, the adapter's plug and the cable for damage, and look at whether the outlet is controlled by a switch or a timer. Outdoor outlets often have a ground-fault protector, a GFCI, that trips in wet weather and cuts power, and pressing its reset button restores it. A camera whose adapter sits outside should be protected from rain, because a wet adapter fails; use a weatherproof enclosure or run the cable inside.

Extension cords that are long or thin cause a voltage drop that makes a camera restart, so use a short cable or a heavier one. If the camera restarts often, check the adapter's rating against the camera's label and replace a failing adapter with one of the same voltage and current. Power cycling the camera, by unplugging it for ten seconds, clears a stuck state.

After a power cut, give the camera and the gateway several minutes to reconnect, restarting the router first and then the gateway, as the SafeWise guide notes for cameras. Keep cables off the ground where they can be cut by a mower or chewed, and use cable clips to hold them against the wall. If the camera has no power with a good outlet and a good adapter, the camera is faulty and the installer should replace it. Never open the camera or the adapter, because mains voltage is dangerous.