bluetooth connection between rpi 4 and android app

i need some help, im trying for a project to comnuticate via bluetooth and send/recieve data between the rpi4 and the phone i connected the phone between the two with noemal bluetooth but when i writen the code(i tried a lot of codes but all was the same) and tried to connect with the app "serial bluetooth terminal" it says: "connection failed read failed socket might closed or timeout read ret ‐1" when i tried simple code like bluedot app and code it worked completely fine so idont know what is the issue, can anyone help me please?

https://github.com/Taher1322/RPi-bluetooth_app/blob/master/dataread.py examples for one of the codes