This is typically caused by a mounting issue. Please check the following:
- Ensure one piece is mounted on the door or window and the other piece is mounted on the frame
- The space between both the transmitter (larger piece) and magnet (smaller piece) should not exceed 3/4"
- Check for any recess in the door/frame. Ensure both pieces are on the same plane
- Ensure the notches on the magnet and transmitter are facing each other
If the sensor is mounted correctly but the sensor is still showing opened, please contact Customer Support for additional troubleshooting assistance.