root@debian[/home/finotti]# apt -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up apache2 (2.4.23-6) ...
info: Executing deferred 'a2enconf apache2-doc' for package apache2-doc
ERROR: Conf apache2-doc does not exist!
dpkg: error processing package apache2 (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 apache2
E: Sub-process /usr/bin/dpkg returned an error code (1)

root@debian[/home/finotti]# apt policy apache2-doc
apache2-doc:
  Installed: 2.4.23-6
  Candidate: 2.4.23-6
  Version table:
 *** 2.4.23-6 500
        500 http://httpredir.debian.org/debian sid/main amd64 Packages
        500 http://httpredir.debian.org/debian sid/main i386 Packages
        100 /var/lib/dpkg/status

root@debian[/home/finotti]# dpkg --configure -a
Setting up apache2 (2.4.23-6) ...
info: Executing deferred 'a2enconf apache2-doc' for package apache2-doc
ERROR: Conf apache2-doc does not exist!
dpkg: error processing package apache2 (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 apache2

root@debian[/home/finotti]# dpkg -P apache2
(Reading database ... 854222 files and directories currently installed.)
Removing apache2 (2.4.23-6) ...
Purging configuration files for apache2 (2.4.23-6) ...
dpkg: warning: while removing apache2, directory '/var/www/html' not empty so not removed
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for systemd (232-3) ...

root@debian[/home/finotti]# apt install apache2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  apache2-suexec-pristine | apache2-suexec-custom
The following NEW packages will be installed:
  apache2
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 229 kB of archives.
After this operation, 584 kB of additional disk space will be used.
Get:1 http://mirror.cc.columbia.edu/debian sid/main amd64 apache2 amd64 2.4.23-6 [229 kB]
Fetched 229 kB in 0s (372 kB/s)
Selecting previously unselected package apache2.
(Reading database ... 854015 files and directories currently installed.)
Preparing to unpack .../apache2_2.4.23-6_amd64.deb ...
Unpacking apache2 (2.4.23-6) ...
Setting up apache2 (2.4.23-6) ...
Enabling module mpm_event.
Enabling module authz_core.
Enabling module authz_host.
Enabling module authn_core.
Enabling module auth_basic.
Enabling module access_compat.
Enabling module authn_file.
Enabling module authz_user.
Enabling module alias.
Enabling module dir.
Enabling module autoindex.
Enabling module env.
Enabling module mime.
Enabling module negotiation.
Enabling module setenvif.
Enabling module filter.
Enabling module deflate.
Enabling module status.
Enabling conf charset.
Enabling conf localized-error-pages.
Enabling conf other-vhosts-access-log.
Enabling conf security.
Enabling conf serve-cgi-bin.
Enabling site 000-default.
Created symlink /etc/systemd/system/multi-user.target.wants/apache2.service → /lib/systemd/system/apache2.service.
Created symlink /etc/systemd/system/multi-user.target.wants/apache-htcacheclean.service → /lib/systemd/system/apache-htcacheclean.service.
insserv: warning: current start runlevel(s) (empty) of script `apache-htcacheclean' overrides LSB defaults (2 3 4 5).
insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of script `apache-htcacheclean' overrides LSB defaults (0 1 6).
Processing triggers for systemd (232-3) ...
Processing triggers for man-db (2.7.5-1) ...