My surge constantly cannot sync to my Fitbit app on my Samsung S6. It will go a day or two then either say "cannot find tracker" or "cannot reach fitbit.com". I have uninstalled and reinstalled the tracker and that works, but it isn't a process I want to do every couple of days. I tried it on my iPhone I have for work and I don't seem to have this problem, but I prefer it to sync to my Samsung (I have unpaired the device from the iPhone).