If you use a Fitbit, you may have noticed that the Fitbit app on an iPhone upgraded to iOS 13.1 will not sync with your Fitbit, complaining of a lack of Bluetooth connectivity, even though Bluetooth is on and the Fitbit is connected in Settings.
Turning off Bluetooth and turning it back on, reconnecting the Fitbit, restarting the iPhone… all three of the most common steps to reestablish a connection fail.
Don’t fret, there is a fix: Delete the Fitbit app from you iPhone and reinstall it from the App Store. Launch the app and it will then ask permission to access Bluetooth (this is what was lacking and causing the issue). Grant permission and your Fitbit app syncing issue is no more!