after updating over the air, the microcontroller does not start/OTA DFU

[Nur2705]

Hi everyone

I apologize in advance for any possible mistakes.

I am new to programming nRF52 series microcontrollers.Having started exploring various possibilities, I ran into one problem that I cannot solve.

Studying OTA DFU for this lesson  OTA DFU tutorial , I stopped at step D.

After the firmware is successfully loaded onto the microcontroller, it stops working(LEDs are off and there is no advertisement).

This error can be corrected only by erasing the chip.

List of used tools:

NRF52 DK

Samsung S7

SDK 17

s132 version 7.2.0.

nrfutil version 6.1.0

[Nur2705]

problem solved
most likely made a mistake due to carelessness