To check the config error

Hi Navin

I believe the issue here is that you're missing the project specific configuration parameters used by the peripheral_uart sample, such as CONFIG_BT_NUS_SEURITY_ENABLED and CONFIG_BT_NUS_UART_BUFFER_SIZE. 

Could you try to copy the Kconfig file from the peripheral_uart sample folder into your own project, and rebuild?

#
# Copyright (c) 2018 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#

source "Kconfig.zephyr"

menu "Nordic UART BLE GATT service sample"

config BT_NUS_THREAD_STACK_SIZE
	int "Thread stack size"
	default 1024
	help
	  Stack size used in each of the two threads

config BT_NUS_UART_BUFFER_SIZE
	int "UART payload buffer element size"
	default 40
	help
	  Size of the payload buffer in each RX and TX FIFO element

config BT_NUS_SECURITY_ENABLED
	bool "Enable security"
	default y
	select BT_SMP
	help
	  "Enable BLE security for the UART service"

config BT_NUS_UART_DEV
	string "UART device name"
	default "UART_0"
	help
	  Name of the used UART device. The sample uses uart0 by default.
	  The UART device should not be used as logger backend.

config BT_NUS_UART_RX_WAIT_TIME
	int "Timeout for UART RX complete event"
	default 50
	help
	  Wait for RX complete event time in milliseconds

config BT_NUS_UART_ASYNC_ADAPTER
	bool "Enable UART async adapter"
	select SERIAL_SUPPORT_ASYNC
	help
	  Enables asynchronous adapter for UART drives that supports only
	  IRQ interface.

endmenu

Then these parameters should be accessible to the build system. 

Best regards
Torbjørn

Thank you Torbjorn,

Now its working fine. I want to know how to find out these type of error. Kindly, explain me 

Hi

Essentially you have to read the build logs carefully, and try to figure out what is wrong with the configuration. 

Granted, some times the logs are hard to understand unless you have a good understanding of the build system, including the Kconfig and device tree. 

Have you followed our tutorials and guides to get started with NCS, suchas the nRF Connect SDK tutorial series?

Also, I would recommend checking out the first course in our new Nordic Academy, available here.
It doesn't really cover Kconfig in a lot of detail, but it provides a lot of other tips and tricks on using the nRF Connect SDK. 

Best regards
Torbjørn