ADT Glass Break Sensor is offline or unavailable

The checks in more detail

Next, the radio link. The sensor talks to the control panel by radio, and distance, metal, masonry and interference weaken the link. A glassbreak sensor is often mounted high in a room with large windows, so the panel in another part of the house may be far away. Move the panel closer or to a central position, keep it away from large metal objects, and check that nothing, such as a new appliance or a router, has been placed between them. If the sensor reappears after a restart of the panel and the sensor, the cause was a temporary link loss.

Placement affects its function as well as its link. It should have a clear line of sight to the windows it protects, within the range given in the instructions, and not be hidden behind curtains or furniture. If it still shows offline with a fresh battery and a short distance, remove it from the system in the app and add it again, following the pairing steps. Test it after, using the system's test mode and, where the model provides one, a glassbreak simulator recommended by ADT. Do not leave a glassbreak sensor offline for long, since the glass it protects is then unprotected.

Contact ADT support with the model and serial number if it will not reconnect. Keep a short log of when the sensor goes offline, since a pattern, such as every evening when a particular appliance runs or every winter morning, points to interference or cold. A microwave oven, a baby monitor and a cordless phone base share the radio bands used by many sensors, so moving one of them or the panel can settle a recurring dropout. In a cold house, batteries lose strength, and replacing them with fresh ones from a trusted brand before winter prevents many offline reports.