I looked through several threads. I reset my One by plugging in to the charger and holding the button down (I did this several times). I turned it off (connect to power, hold button in for 12 sec, disconnect from power). Then I powered down my iPhone 11. Then I powered up the iPhone. Once it was on, and I opened it, I powered my One on. Then I opened the Fitbit app on my phone. It was THEN that it finally synched up! What an ordeal! But it's working again.
Also, during the time it wasn't synching, it was draining power fast! Like less than a day. I wonder if it was "looking" for somewhere to sync? I'll have to keep any eye open. It's several years old so it might just be nearing end of life? I hope not! Hope my suggestion helps someone!
Best AnswerStep count on fitbit is 7863. Step count on fitbit app is 7139. I keep trying to sync.
Best AnswerI have been trying for a few days to get my Fitbit One to sync with no luck.This worked for me. Thank you very much.