From the extension of your key file (key.ppk), my guess is that you're using PuTTY to connect to the VMs. Is that correct?   PuTTY uses a different key format than OpenSSH clients. If the above is correct, try converting your key.ppk to OpenSSH format using PuTTYgen (see link below) and try again using the converted file.   https://www.thegeekdiary.com/how-to-convert-puttys-private-key-ppk-to-ssh-key/   Cheers, André ... View more