The FitOn app on Fitbit requires Wi-Fi access. You can check the Wi-Fi status of your watch by following these steps:
Go to the Settings app on your watch
Tap on About
Scroll down to IP Address. If it says Wi-Fi off then your watch is not connected.
Note: This feature isn’t available on Fitbit Sense 2, Fitbit Versa Lite Edition, or Fitbit Versa 4.
Easily reconnect your watch to Wi-Fi by following these steps:
Open up the Fitbit app on your phone
At the top left corner of the Today tab, tap your Account icon
Tap on your Device
Scroll down to find and tap Wi-Fi Settings
Follow the on-screen instructions to reconnect or tap "Add Network" to connect to a new network
Find the network that you want to connect your watch to
Once done, you will see that your device has been connected to the Wi-Fi network
If you have any problems or questions, please contact the Customer Support Team of Fitbit.