I thought it wasn't tracking, but now I think it just tracks… oddly. What I mean is, first I discovered (IDK where) that it won't track sleep less than I think it's 3 hours or something. I don't know exactly what it's measuring to decide if I am sleeping. But you might try, as I did, going into the app and setting up sleep, sleep-prep preferences ( it will buzz and alarm when you set up reminder that it's time to e.g brush your teeth, put your pjs on, and turn off devices etc.
But it's still doing funny tracking if I fall asleep and then get up in say and hour to go to the bathroom, it doesn't track at all under a certain time (not really sure what that is). Also, It tracks by the day, so if I go to sleep before midnight (which I haven't so far, so I can't say) I'm not sure how it adds that time?
I've seen it say I only slept like 2hours, when I'm sure it was more than that.
You might also try adjusting the strap, looser/tighter ? IDK but just try that and see if it makes a difference. Then also, if the charge is low on the battery, it may not have enough to track an sync. ?
Try recharging and then reboot phone too. These are suggestions under the heading 'charge 3 heart rate not tracking' (or something like that).
I'm trying to get it to sync with my WW app. That's not happening either.
Blessings,
