package apache2 2.4.41-4ubuntu3 failed to install/upgrade: ERROR: Conf phppgadmin does not exist!

[Ko Ko Zin]

Encounter the problem while upgrading from Ubuntu-18.04 LTS to Ubuntu-20.04 LTS.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: apache2 2.4.41-4ubuntu3
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
Apache2ConfdDirListing: False
Apache2Modules:
 AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message
 httpd (pid 1757) already running
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
Date: Fri Apr 24 18:47:49 2020
ErrorMessage: installed apache2 package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2016-06-03 (1420 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2
SourcePackage: apache2
Title: package apache2 2.4.41-4ubuntu3 failed to install/upgrade: installed apache2 package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to focal on 2020-04-24 (0 days ago)

[Rafael David Tinoco (rafaeldtinoco)]

This is the error during upgrade:

Preparing to unpack .../840-phppgadmin_7.12.1+dfsg-1_all.deb ...
Unpacking phppgadmin (7.12.1+dfsg-1) over (5.1+ds-3) ...
...
Setting up phppgadmin (7.12.1+dfsg-1) ...
Installing new version of config file /etc/phppgadmin/config.inc.php ...
Package apache2 is not configured yet. Will defer actions by package phppgadmin.
...
info: Executing deferred 'a2enconf phppgadmin' for package phppgadmin
ERROR: Conf phppgadmin does not exist!
dpkg: error processing package apache2 (--configure):
 installed apache2 package post-installation script subprocess returned error exit status 1

The module wasn't able to be enabled after apache2 (and the module) was updated.

[Bryce Harrington (bryce)]

The log shows there was a configuration question for postfix, that caused apache2 to be left unconfigured:

Setting up postfixadmin (3.2.1-3) ...
Installing new version of config file /etc/apache2/conf-available/postfixadmin.conf ...

Configuration file '/etc/postfixadmin/config.inc.php'
 ==> Modified (by you or by a script) since installation.
 ==> Package distributor has shipped an updated version.
   What would you like to do about it ? Your options are:
    Y or I : install the package maintainer's version
    N or O : keep your currently-installed version
      D : show the differences between the versions
      Z : start a shell to examine the situation
 The default action is to keep your current version.
*** config.inc.php (Y/I/N/O/D/Z) [default=N] ?
Package apache2 is not configured yet. Will defer actions by package postfixadmin.
[...]

Setting up phppgadmin (7.12.1+dfsg-1) ...
Installing new version of config file /etc/phppgadmin/config.inc.php ...
Package apache2 is not configured yet. Will defer actions by package phppgadmin.
[...]

Setting up apache2 (2.4.41-4ubuntu3) ...
info: Executing deferred 'a2enconf phppgadmin' for package phppgadmin
ERROR: Conf phppgadmin does not exist!
dpkg: error processing package apache2 (--configure):
 installed apache2 package post-installation script subprocess returned error exit status 1