If you would like further help, you will need to give more information, like:
What is your app trying to do?
Which version of the micro:bit do you have?
Which versions of the BLE and micro:bit extensions are you using?
Maybe attach a .hex and a .aia file.
Oh, I'm a newbie of this sector. It worked. Just some program pre-installed inside my microbit overlapped the new one. haha thankssss.
..... that phone has the most recent Google security measures, so along with Bluetooth being switched on, Location should also be switched on.