Possible causes of this alert

Sometimes a sensor can be slightly out of range. Try placing the sensor closer to the SmartHub or moving the SmartHub closer to sensor. Keep in mind that the SmartHub connection works best when it's centrally located to all the sensors.

Take the cover off the sensor and press the orange button for approximately 5 seconds. The light on the sensor should flash blue. If it doesn't try reseating the batteries or replace them with Lithium Ion batteries. If those still don't work contact us at support@smartac.com

This could be a combination of low battery and sensor placement. Please refer to the those sections.