@Charonrg what phone model and operating system are you using? Which Fitbit OS and Fitbit mobile app version are you using? What steps have you tried so far?
Best AnswerI agree with @Marrrmaduke, when asking about a phone problem it is helpful to know what phone we are asking about?
Everything doesn't tell us much.
For now I'll point to the Fitbit help doc. But I'm sure you have read it already.
Why won't my Fitbit device sync?