Q:

subprocess installed post-installation script returned error exit status 10

I had openssh-server working on my dedicated server running proxmox, but everytime I tried to upgrade anything I got this error:
dpkg:error processing package openssh-server (--configure):
subprocess installed post-installation script returned error exit status 10

So I read on forums that I should uninstall and purge openssh-server and install it again therefore I ran proxmox shell which doesn't need ssh to connect to server and remove openssh-server.
Now I cannot install it and I don't have ssh access to my server.
I tried this:
$ dpkg --configure -D 777 openssh-server
...
D000400:       checking breaker openssh-sftp-server:amd64 virtbroken <none>
D000400:     checking virtbroken openssh-server
Setting up openssh-server (1:7.4p1-10+deb9u3) ...
D000002: fork/exec /var/lib/dpkg/info/openssh-server.postinst (   configure   )
dpkg: error processing package openssh-server (--configure):
 subprocess installed post-installation script returned error exit status 10
D000001: ensure_diversions: same, skipping
Errors were encountered while processing:
 openssh-server

I also tried removing openssh-server* from /var/lib/dpkg/info and installing it again I didn't have any success.
My OS is Debian Stretch and I installed proxmox kernel on it.
How can I install openssh-server with these situation?

A:

At last I couldn't config openssh-server but I edit my /etc/apt/sources.list and added these lines:
(As my server is in Hetzner Co.)
deb http://mirror.hetzner.de/debian/packages jessie main contrib non-free
deb http://mirror.hetzner.de/debian/security jessie/updates main contrib non-free
deb http://mirror.hetzner.de/debian/packages jessie-updates main contrib non-free

Then I installed the latest previous version of openssh-server which it was on jessie mirror.
Like this:
apt update
apt remove openssh-client openssh-sftp-server openssh-server
apt clean
apt install openssh-client=1:6.7p1-5+deb8u4
apt install openssh-sftp-server=1:6.7p1-5+deb8u4
apt install openssh-server=1:6.7p1-5+deb8u4

You can also check any package versions you can install by this:
apt-cache showpkg package
apt-cache showpkg openssh-server

