SimpliSafe Glassbreak Sensor will not reset or needs to be reset safely

The checks in more detail

If the sensor is offline or the app cannot find it, remove it from the system in the app, which clears its pairing, and then reset it. SimpliSafe's help page for the glassbreak sensor describes how to put it back into pairing mode, and the steps depend on the version of the sensor, so read the page for your sensor. After the reset, add the sensor in the app by choosing to add a device, then follow the prompts. Give it a name, such as Living Room Glassbreak, so that alerts are clear. After pairing, test the sensor with the test mode in the app.

SimpliSafe describes using a test tone from a device made for the purpose, or the in-app test, since breaking real glass is not necessary or safe. Place the sensor on a wall or ceiling according to the guide. A sensor that works in a test and gives false alarms may be near a noise source or beyond its recommended range. Keep spare batteries on hand. If the sensor will not pair after a reset and a new battery, it may have a fault, and SimpliSafe can check it by the serial number and replace it in warranty. Do not break glass to test the sensor.

A glassbreak sensor is sensitive to the sound of glass, not to vibration, so it needs a room where that sound can travel to it; a sensor in the next room, behind a closed door, hears little. Large windows with heavy curtains absorb the sound, and glass that is laminated or double glazed breaks more quietly than a single pane. Think about the windows that an intruder would be most likely to use, and place the sensor where it can hear them. In a household with a dog that barks at the window, or a television that plays gunshots, test the sensor for false alarms before you rely on it, and write the date of each battery change on the back.