O site da Apache não está disponível

Question

Eu tenho um servidor Ubuntu 16 rodando como uma VM no meu PC. Eu já tenho uma série de sites em execução sem qualquer problema. O site padrão do Apache está bem. Eu instalei um produto chamado otrs ( link ) e não encontrei nenhum erro. No entanto, quando tento navegar para o site ( link ), recebo um 404.

Eu posso ativar e desativar o site através do Apache (a2ensite e a2dissite) sem nenhum erro reportado. Não há erros nos arquivos de log do Apache. Eu estou um pouco em uma perda para saber o que fazer a seguir. Qualquer sugestão recebida com gratidão.

Se eu correr:

sudo ls -ll /etc/apache2/sites-available/;ls -ll /etc/apache2/sites-enabled/;cat /etc/apache2/sites-enabled/*.conf;a2query -s

Eu recebo o seguinte:

total 12
-rw-r--r-- 1 root root 1332 Mar 19  2016 000-default.conf
-rw-r--r-- 1 root root 6338 Apr  5  2016 default-ssl.conf
lrwxrwxrwx 1 root root   44 Dec 20 07:16 otrs.conf -> /opt/otrs/scripts/apache2-httpd.include.conf
total 0
lrwxrwxrwx 1 root root 35 Nov  8 04:24 000-default.conf -> ../sites-available/000-default.conf
lrwxrwxrwx 1 root root 28 Dec 20 08:00 otrs.conf -> ../sites-available/otrs.conf
<VirtualHost *:80>
        # The ServerName directive sets the request scheme, hostname and port that
        # the server uses to identify itself. This is used when creating
        # redirection URLs. In the context of virtual hosts, the ServerName
        # specifies what hostname must appear in the request's Host: header to
        # match this virtual host. For the default virtual host (this file) this
        # value is not decisive as it is used as a last resort host regardless.
        # However, you must set it for any further virtual host explicitly.
        #ServerName www.example.com

        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/html

        # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
        # error, crit, alert, emerg.
        # It is also possible to configure the loglevel for particular
        # modules, e.g.
        #LogLevel info ssl:warn

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

        # For most configuration files from conf-available/, which are
        # enabled or disabled at a global level, it is possible to
        # include a line for only one particular virtual host. For example the
        # following line enables the CGI configuration for this host only
        # after it has been globally disabled with "a2disconf".
        #Include conf-available/serve-cgi-bin.conf
</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet
# --
# added for OTRS (http://otrs.org/)
# --

ScriptAlias /otrs/ "/opt/otrs/bin/cgi-bin/"
Alias /otrs-web/ "/opt/otrs/var/httpd/htdocs/"

<IfModule mod_perl.c>

    # Setup environment and preload modules
    Perlrequire /opt/otrs/scripts/apache2-perl-startup.pl

    # Reload Perl modules when changed on disk
    PerlModule Apache2::Reload
    PerlInitHandler Apache2::Reload

    # general mod_perl2 options
    <Location /otrs>
#        ErrorDocument 403 /otrs/customer.pl
        ErrorDocument 403 /otrs/index.pl
        SetHandler  perl-script
        PerlResponseHandler ModPerl::Registry
        Options +ExecCGI
        PerlOptions +ParseHeaders
        PerlOptions +SetupEnv

        <IfModule mod_version.c>
            <IfVersion < 2.4>
                Order allow,deny
                Allow from all
            </IfVersion>
            <IfVersion >= 2.4>
                Require all granted
            </IfVersion>
        </IfModule>
        <IfModule !mod_version.c>
            Order allow,deny
            Allow from all
        </IfModule>
    </Location>

    # mod_perl2 options for GenericInterface
    <Location /otrs/nph-genericinterface.pl>
        PerlOptions -ParseHeaders
    </Location>

</IfModule>

<Directory "/opt/otrs/bin/cgi-bin/">
    AllowOverride None
    Options +ExecCGI -Includes

    <IfModule mod_version.c>
        <IfVersion < 2.4>
            Order allow,deny
            Allow from all
        </IfVersion>
        <IfVersion >= 2.4>
            Require all granted
        </IfVersion>
    </IfModule>
    <IfModule !mod_version.c>
        Order allow,deny
        Allow from all
    </IfModule>

    <IfModule mod_filter.c>
        <IfModule mod_deflate.c>
            AddOutputFilterByType DEFLATE text/html text/javascript application/javascript text/css text/xml application/json text/json
         </IfModule>
    </IfModule>

</Directory>

<Directory "/opt/otrs/var/httpd/htdocs/">
    AllowOverride None

    <IfModule mod_version.c>
        <IfVersion < 2.4>
            Order allow,deny
            Allow from all
        </IfVersion>
        <IfVersion >= 2.4>
            Require all granted
        </IfVersion>
    </IfModule>
    <IfModule !mod_version.c>
        Order allow,deny
        Allow from all
    </IfModule>

    <IfModule mod_filter.c>
        <IfModule mod_deflate.c>
            AddOutputFilterByType DEFLATE text/html text/javascript application/javascript text/css text/xml application/json text/json
         </IfModule>
    </IfModule>

    # Make sure CSS and JS files are read as UTF8 by the browsers.
    AddCharset UTF-8 .css
    AddCharset UTF-8 .js

    # Set explicit mime type for woff fonts since it is relatively new and apache may not know about it.
    AddType application/font-woff .woff

</Directory>

# Allow access to public interface for unauthenticated requests on systems with set-up authentication.
# Will work only for RegistrationUpdate, since page resources are still not be loaded.
# <Location /otrs/public.pl>
#     <IfModule mod_version.c>
#         <IfVersion < 2.4>
#             Order allow,deny
#             Allow from all
#         </IfVersion>
#         <IfVersion >= 2.4>
#             Require all granted
#         </IfVersion>
#     </IfModule>
#     <IfModule !mod_version.c>
#         Order allow,deny
#         Allow from all
#     </IfModule>
# </Location>

<IfModule mod_headers.c>
    # Cache css-cache for 30 days
    <Directory "/opt/otrs/var/httpd/htdocs/skins/*/*/css-cache">
        <FilesMatch "\.(css|CSS)$">
            Header set Cache-Control "max-age=2592000 must-revalidate"
        </FilesMatch>
    </Directory>

    # Cache css thirdparty for 4 hours, including icon fonts
    <Directory "/opt/otrs/var/httpd/htdocs/skins/*/*/css/thirdparty">
        <FilesMatch "\.(css|CSS|woff|svg)$">
            Header set Cache-Control "max-age=14400 must-revalidate"
        </FilesMatch>
    </Directory>

    # Cache js-cache for 30 days
    <Directory "/opt/otrs/var/httpd/htdocs/js/js-cache">
        <FilesMatch "\.(js|JS)$">
            Header set Cache-Control "max-age=2592000 must-revalidate"
        </FilesMatch>
    </Directory>

    # Cache js thirdparty for 4 hours
    <Directory "/opt/otrs/var/httpd/htdocs/js/thirdparty/">
        <FilesMatch "\.(js|JS)$">
            Header set Cache-Control "max-age=14400 must-revalidate"
        </FilesMatch>
    </Directory>
</IfModule>

# Limit the number of requests per child to avoid excessive memory usage
MaxRequestsPerChild 4000
otrs (enabled by site administrator)
000-default (enabled by site administrator)

Tudo parece estar em ordem