For the last maybe 3-5 months, I've noticed that my charge 2 sometimes wouldn't sync successfully, even when directly beside the phone. It tended to work if I reset my phones (galaxy a70) Bluetooth. Then it said I needed to update my charge 2, and I tried a bunch but it was always unsuccesful.
Yesterday when it again wouldn't sync, I tried everything - reset Fitbit, Bluetooth on and off, "forgot" the device... Finally I unpaired them and tried to pair them again, but it won't work. I get the code on my Fitbit, enter it into the app, it says connecting... And then always fails.
So now it's not even paired, it's basically useless...