We're sorry you're facing this issue. 

Can you please try following the below steps and see if they resolve the issue?
1. Please check if Bluetooth is on/off on the band as well as the phone.

2. Restart the App.

3. Pair / UnPair the band (by going to Settings).

4. Please press the Sync icon on the top right of the home Screen

If it's still unsuccessful please let us know.