When adding subdomain it's redirecting back to main domain / Ubuntu 16.04 / Apache

The following steps worked for me. 1: add virtual host like the following with chmod 664 and chown www-data:www-data

<VirtualHost *:80>
        ServerAdmin youemail@sth.com
        DocumentRoot /var/www/subdomain
        ServerName subdomain.hashmatwaziri.com
        ServerAlias www.subdomain.hashmatwaziri.com
        <Directory /var/www/subdomain/>
            Options Indexes FollowSymLinks
            AllowOverride All
            Require all granted
        </Directory>

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

        <IfModule mod_dir.c>
            DirectoryIndex index.php index.pl index.cgi index.html index.xhtml index.htm
        </IfModule>

RewriteEngine on
RewriteCond %{SERVER_NAME} =hashmatwaziri.com
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

2: sudo add-apt-repository ppa:certbot/certbot (add the repository) 3: sudo apt install python-certbot-apache (Install Certbot’s Apache package with apt)

4: type “certbot” 5: select the newly created virtual host 6: and you are all good to go. cheers

Did you enabled your VirtualHost? As I see, you created new file for subdomain VH, if you did it - you need to enable it using a2ensite:

sudo a2ensite demo.domain.com

Make sure to restart after any change you do to the config:

sudo systemctl restart apache2

Try to access subdomain again. If you still see wrong page, try clearing cache or going to Incognito mode.