ADT Doorbell Camera is offline or unavailable

The checks in more detail

If the doorbell still shows offline, check the signal at the door with your phone, since a weak link is the commonest cause. SafeWise's guide adds that you should delete the doorbell from the system and add it back if it will not reconnect, and, if needed, reset it with the button on the back for fifteen seconds. A phone that is on mobile data or a VPN may show the doorbell offline incorrectly, so check on home Wi-Fi. A doorbell that goes offline at a regular time may be affected by a router restart schedule or by interference at that time, and a doorbell that goes offline after rain may have a power problem from moisture at the wiring.

A wired doorbell with a weak transformer loses connection when the chime rings. Check the app for a service or firmware notice, since an update can briefly take the doorbell offline. Keep a log of the times and the light's state for the installer. If the app shows the doorbell offline but a visitor presses it and you hear the chime, the chime is wired separately, so a ringing chime does not prove the doorbell is online. Move the router nearer or add a node if the signal is poor. If nothing restores it, the doorbell may be faulty and the installer should replace it. Check the app for a service notice before you reset anything:

when ADT or the camera maker rolls out an update, a doorbell can drop off for a few minutes while it installs and then return by itself. Also check whether the doorbell shows offline only on your phone; ask another person with access to look, because a phone on a VPN, a data-saving mode or a different network can show a false offline status. If the doorbell comes back when you stand at the front door with your phone on its Wi-Fi, the fault is the signal on the way to the door. Photograph the router lights and the doorbell's light when it is offline, which gives the installer something to work with.