Problem with Electron

[internetserver]

Hello I have a problem to flash the bootloader. My Electron shows only LED on D7. I connected a P0 to the Electron and I checked everything several times.

But nothing happens:

Do you have a dead device and wish to continue? [y,N]:y Unknown ACK (5) received. Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y SWD Fault error Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y SWD Fault error Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y SWD Parity error Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y SWD Parity error Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y Unknown ACK (5) received. Please double check the wiring, then try again. Do you have a dead device and wish to continue? [y,N]:y warning: unexpected idcode: 8ae8053f SWD Protocol error Do you have a dead device and wish to continue? [y,N]:y Unknown ACK (5) received.

What is wrong? Is my Electron dead? What means? "warning: unexpected idcode: 8ae8053f SWD Protocol error"

Thanks for help

Nils