Flash downloading and erasing problem & Cannot detect in nrfGO

[AlexW]

Hello together,

I am experiencing problems with the nrf52840.

I got the BLE_APP_Blinky example to run.
Now I am trying to get the BLE_THROUGHPUT example experiment to run, but I have problems with downloading the code to the board:
Error: Flash Download failed - 'Cortex-M4'
when I try to download the softdevice.

Error: Flash Download failed - Could not load file
when I try to download the main code.

I read about erasing the chip before downloading a softdevice, but my board won't be detected in nrfGO Studio so that I could erase the chip.
Similar, the J-Link Commander could not connect to the board.

I read about the issue for days, but I coundn't get the BLE-throughput-test to work on the boards anymore.
(I have 2 nrf52840 and 1 nrf52832 available)

I am happy about any help.

[AlexW]

I switched to SEGGER Studio for now
with this program flashing and all the stuff works finde for now. Thanks so far.