Background App Refresh must be enabled in your Android device for anything to occur in the background while the app is not on the foreground/or if the device is locked.
How to enable background app refresh
Step 1
From the start screen, pull down the notification bar for Settings.
Tap the gear symbol in the top right-hand corner.
Step 2
In Settings, click on Connections.
Step 3
In the Connections menu, tap Data Usage.
Step 4
On the Data usage page, click Mobile data usage.
Choose Hubstaff.
Step 5
Under the Application data usage page of Hubstaff, enable Allow Background data usage.
