

Hello,
Please make sure to have DEBUG defined in your preprocessor defines, like shown in the included image:
This will make your logger output a detailed error message whenever a non-NRF_SUCCESS error is passed to an APP_ERROR_CHECK.
Do this, and check the returned error code against the returning function's API Reference to see how you may rectify it.
Best regards,
Karl
same settings i have done
What does your logger output in this case?
Could you confirm that you have made this configuration in the common configuration?
Best regards,
Karl
APP_TIMER_V2
APP_TIMER_V2_RTC1_ENABLED
BOARD_PCA10056
CONFIG_GPIO_AS_PINRESET
FLOAT_ABI_HARD
INITIALIZE_USER_SECTIONS
NO_VTOR_CONFIG
NRF52840_XXAA
yes done in common configuration only
I do not see your DEBUG define present in this list.
Please make sure to add it, and run the program again.