Thank you all for your valuable replies. Here i will give more clarity about my problem_
1- I didn't use voltage divider ckt. (Will it results in this kind of error ?).
2- I have used my own app which is created by using app inventor MIT, I referred this link-
3- Red LED is blinking in some frequency when I scanned using a smartphone, I got the device ID listed in available BT, and I'm able to pair using 1234 pwd.
I will follow these instruction MR. @GolamMostafa , @cattledog, and @Nick_Pyner soon..