Why can't I make my wife's Galaxy 3 mini (GT-18200L) connect with her FitBit tracker?

[AC Question]

Bought my wife a FitBit tracker for her birthday last July presuming it would work with her Microsoft Surface tablet. It didn't. Now she got a Galaxy 3 mini (GT-18200L) and we still seem to have a problem with "cannot find tracker". It only works through my Galaxy 4 mini via the bluetooth. Is there a solution to this problem? Regards Peter