I go this error late Sunday night after Daylight Savings Time. The clocks rolled back an hour, adding an hour to the day, my pedometer reset at 11:00pm instead of midnight, and then steps on my Samsung Gear 2 and S Health were not in sync, plus the error you described.
I just got off the phone with Samsung tech support, and they escalated my call. It seems that it's a software issue (at least partly) related to the time change... ETA for a fix is about a week.
Hope this helps. This is my first AndroidCentral post ever, but have gotten lots of good info here. Cheers to everyone...