package ssmtp 2.64-7 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2

[John Blanchard]

Upgrade from 12.04.4 to 14.04.2

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: ssmtp 2.64-7
ProcVersionSignature: Ubuntu 3.13.0-46.77-generic 3.13.11-ckt15
Uname: Linux 3.13.0-46-generic i686
ApportVersion: 2.14.1-0ubuntu3.7
Architecture: i386
Date: Wed Mar 11 20:04:01 2015
DuplicateSignature: package:ssmtp:2.64-7:subprocess installed post-installation script returned error exit status 2
ErrorMessage: subprocess installed post-installation script returned error exit status 2
InstallationDate: Installed on 2012-01-06 (1160 days ago)
InstallationMedia: Ubuntu 10.04.3 LTS "Lucid Lynx" - Release i386 (20110720.1)
SourcePackage: ssmtp
Title: package ssmtp 2.64-7 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2
UpgradeStatus: Upgraded to trusty on 2015-03-11 (0 days ago)
mtime.conffile..etc.ssmtp.revaliases: 2013-12-05T09:41:33.408292

[Launchpad Janitor (janitor)]

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

[Grâce (grace-musuvaho)]

Please help me :(