Diagnosis
The sensor’s backplate has been removed from the door/window, or it thinks it has. This triggers the anti-tamper alert.
How to Fix It
Physically remount the sensor. Press the main sensor body firmly onto the mounted backplate until it clicks. Then, manually open and close the door/window it’s on several times. The ‘tampered’ status should clear in the app within a minute.
IF THAT DIDN’T WORK The tiny tamper switch pin inside the sensor or on the backplate might be stuck. Inspect both for debris. Gently press the pin on the sensor with a toothpick to ensure it moves freely.
Heads Up
If you take the sensor off its mount for battery changes, do it quickly and reattach it immediately. Leaving it off for more than a minute can trigger the tamper alert.