ADT Doorbell Camera has power or battery problems

The checks in more detail

The cause is usually a weak or wrong transformer, a loose wire at the terminals or a chime that pulls too much current. Check that the transformer's voltage and rating match the doorbell's requirements, as the manual states, and that the wires at the doorbell and at the transformer are tight. A battery model shows a low-battery message in the app, and the fix is to charge or replace the battery according to its instructions.

Cold weather reduces battery life, so a doorbell in a cold climate needs more frequent charging. A doorbell that is dark may have lost power at the breaker or the transformer, so check the breaker, and note that many installers turn off the circuit to fit it and forget to switch it back on. Do not touch wires while the power is on, because the voltage at the transformer's primary side is mains. Use a qualified electrician for the transformer.

If the doorbell works but restarts when you press the button, the transformer cannot deliver enough current, and a larger one often solves it. A mechanical chime that is old may also need a diode or a different connection, which the installer can fit. If you have a battery model and the battery drains in days, check the Wi-Fi, because a weak signal makes the doorbell work harder, and reduce the motion sensitivity and the zones so that it wakes less often.