Likely the connection between the phone and the vivofit need to be redone. Make sure to use the Garmin Connect App (not android Bluetooth settings) to pair with your Garmin with your phone. Follow these steps and video:
Remove all your Garmin devices from from Garmin Connect App (Menu >> Garmin devices)
"Unpair" all Garmin devices in android Bluetooth settings
If you have any other mobile devices also unpair the Garmin from those devices
Reboot your phone, restart the watch
On your Garmin device place into "pairing mode." Hold the device key until PAIR appears to manually enter pairing mode.
