I have a Fitbit Charge 3 and use it only for sleep tracking. I activate Bluetooth and GPS on my Android phone when I need to sync. Each morning I try to sync the sleep data to get better insights in my daily performance. It's always a difficult and frustrating process. If it takes less that five minutes, it makes my day (that's sarcasm).
When I wake up, I enable Bluetooth and GPS, open the Fitbit app, pull down to sync, and immediately it says "syncing" and the green bar appears and grows longer. Then I go take a shower, and when I come back it is always the same: 0 steps, meaning that syncing didn't happen. I pull down another time, I pull down many times, and I get "syncing", then "searching for device", then "device not found", and you can repeat that for ten minutes or more. One solution is to reboot my phone, but that's so Windows 95.
The following article suggest to enable "always on syncing", to reinstall the Fitbit app on your phone, and to re-pair the Fitbit. Another great solution. Fitbit should "re-pair" their sync process instead of this horrible hack.
https://www.androidauthority.com/fitbit-problems-issues-732505/
I'm not the only one with the problem, so I can't believe that Fitbit doesn't know about this. All their employees probably wear these devices and some should have this same problem, not? Or do they all have Apple Watches? Look at this:
https://community.fitbit.com/t5/forums/searchpage/tab/message?q=sync
Endless pages of problems with syncing going back 5 years or more, many with more than 10 pages of replies with people reporting the same problem.
How difficult is it to setup a proper syncing process between a smartwatch and a phone nowadays? It's 2020 - bluetooth is around for a decade. Fitbit is a big brand with millions of users.
How is it possible that this works so bad and that they can't or won't fix such basic functionality?