Retry "Hello Thermostat" voice trigger phrase with a brief pause between words. You may want to move closer to thermostat and/or raise your voice slightly when retrying the voice trigger. Please ensure your thermostat is connected to your Wi-Fi network for voice control operation. To improve voice trigger phrase recognition, you should adjust the voice sensitivity level. Go to Menu>Voice Control and select the Sensitivity option on your touch screen. A slider bar will appear which indicates your current sensitivity setting. You should adjust your sensitivity level to a higher number to help improve the recognition of the trigger command (Hello Thermostat). You may modify the voice control sensitivity multiple times to optimize your voice experience.