If you are using the Wahoo Fitness App, be sure to hit "save" on the sensor pairing page. Many people forget to save their settings during the pairing process. If you are using one of Wahoo’s partner Apps, each App pairs a little differently, but a good place to start is in the App’s “settings” section. Remember, you have to pair the monitor in each App you want to use. Pairing in the Wahoo Fitness App does not automatically pair it in other Apps.