Hi, the error message is below, the password message does not appear any more. The board was powered by another computer through the usb interface. i changed that and now it is powered from an external supply. I can ping the board but impossible to upload.
I'm using the Arduino Mega 2560 optiboot as board and Arduino OTA (Ip...) as programmer
Actually it seems to come from the com port...
Arduino : 1.8.12 (Windows 10), Carte : "Arduino Mega 2560 (Optiboot)"
avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
System wide configuration file is "C:\Users\me\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"
Using Port : COM6
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: ser_open(): can't open device "\.\COM6": Le fichier sp�cifi� est introuvable.
Problème de téléversement vers la carte. Voir http://www.arduino.cc/en/Guide/Troubleshooting#upload pour suggestions.