*Note:
This FAQ applies only to the MSG100.

The sensor is probably not well installed or is defective. You can follow the points below to troubleshoot.

1. Manually move the two sensor parts close (less than 1/4 inch) or apart, to check whether the Meross app updates the right status.

2. Ensure the sensor cables are securely connected to the smart garage door opener. Locate the red connector (refer to the photo below) and briefly short the two pins inside it. If the app shows "Closed" status, reconnect the red connector firmly. 

If both points do not help and your MSG100 is still under the warranty, please contact us for a replacement.

*Note: 
If your order is out of warranty, you need to buy the sensor here.