For security reasons, most of the Linux distro don’t allow you to do anything as root by default. Due to this reason, once we deploy a turnkey linux on proxmox, we can’t access using putty.
SSH is configured by default to deny root logins.
You can configure your SSH server to allow root logins by editing the sshd_config file.
From the Proxmox VM/LXC container, navigate to
sudo nano /etc/ssh/sshd_config
Add the following line as,
Save and Exit
sudo systemctl restart ssh
Now your putty shall able to connect on your vm using ssh.