LittleBird requires Bluetooth access to be enabled for the LittleBird app, to be able to unlock the doors around your porperty. Here's how to enable it on iOS devices
1) Open the "Settings" app
2) Scroll down to "Apps", and tap that
3) Find "LittleBird" in the app list, and tap it to open
4) Find "Bluetooth" in the resulting setting list, and enable it, turning the slider from gray to green.
5) Force-close the LittleBird app, and re-open it.