package ssmtp 2.64-8ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Jean Simon]

installing

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: ssmtp 2.64-8ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-35.40-generic 4.2.8-ckt5
Uname: Linux 4.2.0-35-generic i686
ApportVersion: 2.20.1-0ubuntu2
Architecture: i386
Date: Fri Apr 22 12:10:17 2016
DuplicateSignature:
 Setting up ssmtp (2.64-8ubuntu1) ...
 hostname: Name or service not known
 dpkg: error processing package ssmtp (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2014-12-30 (478 days ago)
InstallationMedia: Lubuntu 13.10 "Saucy Salamander" - Release i386 (20131016.1)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1
 apt 1.2.10ubuntu1
SourcePackage: ssmtp
Title: package ssmtp 2.64-8ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2016-04-22 (0 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.