One not syncing with blue tooth.

[Slsuther]

My one will not sync wit any bluetooth device, not just Samsung.  I have called Fitbit several times with no resolution.

[Baltoscott]

@Slsuther -- this happens fairly often to me when I try to sync with my iPhone.  It turns out that what has happened -- every single time -- is that my One was linked to my iPad while I was trying to sync to the phone. Bluetooth seems to somehow be "sticky" on the iPad, whether or not I have the fitbit app open on it.  To "fix" I temporarily turn off Bluetooth on the iPad, restart my iPhone, and then sync.  Since you have also been trying to sync with multiple devices, you may be having a similar problem.  I would turn off Bluetooth on every device -- including your computer -- that you have ever synced your One with, then restart your phone and try syncing again.