/etc/apache2/sites-available/default-ssl.conf This file is very big and I only modified these two lines to change the cert

...
SSLCertificateFile /etc/apache2/ssl/apache.crt
SSLCertificateKeyFile /etc/apache2/ssl/apache.key
...

/etc/apache2/sites-available/default-ssl.conf This file is very big, I will remove the comments

<IfModule mod_ssl.c>
        <VirtualHost _default_:443>
                ServerAdmin webmaster@localhost

                DocumentRoot /var/www/html

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

                SSLEngine on

                SSLCertificateFile /etc/apache2/ssl/apache.crt
                SSLCertificateKeyFile /etc/apache2/ssl/apache.key

                <FilesMatch "\.(cgi|shtml|phtml|php)$">
                                SSLOptions +StdEnvVars
                </FilesMatch>
                <Directory /usr/lib/cgi-bin>
                                SSLOptions +StdEnvVars
                </Directory>
        </VirtualHost>
</IfModule>

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These are the config files, in case they might be of help. With the exception of nextcloud.conf, I think the other ones are the default ones.

/etc/apache2/sites-available/nextcloud.conf

Alias /nextcloud "/var/www/nextcloud/"

<Directory /var/www/nextcloud/>
  Require all granted
  AllowOverride All
  Options FollowSymLinks MultiViews

  <IfModule mod_dav.c>
    Dav off
  </IfModule>

</Directory>

/etc/apache2/sites-available/000-default.conf

<VirtualHost *:80>
   ServerAdmin example@example

   RewriteEngine On
   RewriteCond %{HTTPS} off
   RewriteRule ^(.*)$ https://%{HTTP_HOST}$1 [R=301,L]
</VirtualHost>

/etc/apache2/sites-available/default-ssl.conf This file is very big and I only modified these two lines to change the cert

...
SSLCertificateFile /etc/apache2/ssl/apache.crt
SSLCertificateKeyFile /etc/apache2/ssl/apache.key
...

/etc/apache2/ports.conf

# If you just change the port or add more ports here, you will likely also
# have to change the VirtualHost statement in
# /etc/apache2/sites-enabled/000-default.conf

Listen 80

<IfModule ssl_module>
        Listen 443
</IfModule>

<IfModule mod_gnutls.c>
        Listen 443
</IfModule>

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/etc/apache2/apache2.conf I suppressed the comments in this file otherwise it gets very big

# This is the main Apache server configuration file...
# ...
# The directory where shm and other runtime files will be stored.
DefaultRuntimeDir ${APACHE_RUN_DIR}

# PidFile: The file in which the server should record...
PidFile ${APACHE_PID_FILE}

# Timeout: The number of seconds...
Timeout 300

# KeepAlive: Whether or not to allow persistent connections...
KeepAlive On

# MaxKeepAliveRequests: The maximum number of requests to allow...
MaxKeepAliveRequests 100

# KeepAliveTimeout: Number of seconds to wait for the next request...
KeepAliveTimeout 5

# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

# HostnameLookups: Log the names of clients or just their IP addresses...
HostnameLookups Off

# ErrorLog: The location of the error log file
ErrorLog ${APACHE_LOG_DIR}/error.log

# LogLevel: Control the severity of messages...
LogLevel warn

# Include module configuration:
IncludeOptional mods-enabled/*.load
IncludeOptional mods-enabled/*.conf

# Include list of ports to listen on
Include ports.conf


# Sets the default security model of the Apache2 HTTPD server...
<Directory />
        Options FollowSymLinks
        AllowOverride None
        Require all denied
</Directory>

<Directory /usr/share>
        AllowOverride None
        Require all granted
</Directory>

<Directory /var/www/>
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
</Directory>

# AccessFileName: The name of the file to look...
AccessFileName .htaccess

# The following lines prevent .htaccess and .htpasswd files...
<FilesMatch "^\.ht">
        Require all denied
</FilesMatch>

# The following directives define some format nicknames...
LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

# Include generic snippets of statements
IncludeOptional conf-enabled/*.conf

# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf

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