Proxmox container and no access via SSH?!

[Svenson]

Hello,

I had an old Ryzen 3 1200 Pc standing around here and thought I'd put some Proxmox (LXC) on it to learn in different districts, etc. Acquire more knowledge etc.

So far no problem. Create CT, assign IP etc.
Via VNC I can access it. 

If I want to try Putty, I get to the login. I can specify user root but he does not accept the password. 

What could be the reason for this?

[geforceGTX]

Root login enabled in the SSH config at all? Is it possible with a normal user?

[Svenson]

root login was disabled (Debian). I could have figured that out myself.
Just like with CentOS 6&7 the OpenSSH server has to be installed. Fortunately Proxmox offers the possibility to create your own templates.

Even if this doesn't fit to the problem mentioned above, Proxmox and its API don't offer the possibility to reinstall the containers apart from stop/delete, rebuild?