Why did I fail to set up my Onvis Smart Motion Sensor SMS2 to Onvis Home app?

(1) Make sure Bluetooth is enabled in your iOS device. 
(2) Make sure your SMS2 is within connecting range of your iOS device.
(3) Before setting up, reset the device by long pressing the button in the hole for about 10 seconds until green LED blinks 3 times.
(4)  Scan the setup code on the device, instruction manual or inner packaging.
(5)  If the app prompts “couldn’t add the device” after scanning the setup code:
      a. remove this SMS2 that was added before and close the app;
      b. restore the accessory to factory settings;
      c. add the accessory again;
      d. update the device firmware to the latest version.