There may be several reasons why the Sensor is not properly communicating with your infrared system. Please login to your web browser login page and ensure the Cello Sensor is online. If the sensor is not online please try rebooting the sensor, if it does not come online within 5 minutes simply plug an ethernet into your computer and the sensor and follow the procedure in the Cello Sensor manual on how to connect the Cello Sensor. If your sensor is online please ensure the Sensor is within viewing angle of your ductless unit the maximum recommended distance is 15ft away from the Sensor with a 180° viewing angle.