Puk sensors
A Puk has stopped reporting
Almost always range or battery. Metal doors block Bluetooth, and the cell lasts about eighteen months.
A Puk that was reporting and now is not has two likely explanations, and you can tell them apart in a minute.
Range
Open the door and watch the app. If the Puk reappears within a few seconds, the door is the problem, not the sensor.
Bluetooth passes through wood, glass and cabinetry without complaint. Metal is what stops it — a steel-doored wine fridge, a safe, a foil-lined humidor. The answer is to move the Tali closer to the zone, not to move the Puk out of it. The Puk’s job is to be inside.
Battery
If it stays missing with the door open, check its age. The cell is a standard CR2032 and lasts around eighteen months. Replacing it is a two-minute job you do yourself — see replacing the battery.
After a change of battery or place
The Puk rejoins on its own. If it does not appear within a minute, bring it close to the Tali, let it reconnect there, then put it back.
Still nothing
Tell us the zone, roughly when it went quiet and how old the battery is, and we will pick it up from there.