For your security, the NineBx app is automatically screen-locked every time it is pushed to the background. This prevents unauthorized access to your NineBx account if others use your device. You can also manually lock your NineBx app screen as described in Screen-locking NineBx.
For added security, it is recommended that you also have your device auto-lock when not in use. The auto-lock feature on your iOS or Android devices allows you to set the amount of time that elapses before the phone automatically locks or turns off the display.
Please refer to instructions from your device manufacturer on how to set auto-lock on your device.