Unable to establish Connection

[rusty3699]

Hi all, I am using this library to send some data from RPI 4B to Android Device(nrf Connect)

Followed all steps and troubleshooting.
Bluez version - 5.37
Raspberry 4B - 8GB RAM

I get this error on terminal after running hellotinyb.cpp
Started = true
Discovered devices:
Class = BluetoothDevice Path = /org/bluez/hci0/dev__*__* Name = * Connected = 1
#*name of device and MAC address(in the above line)
Stopped = true
terminate called after throwing an instance of 'tinyb::BluetoothException'
what(): Timeout was reached
Aborted

Whereas on the android device,
Error 133(0x85): GATT Error
Disconnected

Am I missing any steps? I am a beginner, can anyone explain me end to end flow for same to get data the data on the android device.
I tried upgrading to latest bluez version 5.55 still same error. Need suggestions for bluez version too if there is any workaround for 5.55 too or it does require ONLY 5.37?

Thank You