Did reboot, apt-get update ; failed with error:
some index files failed to download, they have been ignored, or old ones used instead.
apt-get install --reinstall openssh-server openssh-client openssh-blacklist ; failed with errors:
Package openssh-server is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or is
only available from another source
E: Package openssh-server has no installation candidate.