Oh course it rejects the Bluetooth @Mrsbugs.
Let's close the Bluetooth settings, open the Fitbit app.
Now we want to log into your Fitbit account and add the tracker to your Fitbit account.
Since you have an account, you want to follow the steps to add a tracker to your account.
Note: The whole procedure happens through the Fitbit app, once the tracker is added to your account the app will pair the tracker to the phone, should it be necessary.
Best Answer