I know this has been asked many times and there a lot of questions and answers regarding this. I've tried all of them but none of them worked for me. I will put here important details regarding my setup

sites-available folder

• 000-default.conf
  
• blogs.ai-labs.conf
• 000-default.conf.save
  
• default-ssl.conf
• ai-labs.co.conf
  
• f5exam.ai-labs.conf
• api.ai-labs.conf

sites-enabled folder

• ai-labs.co.conf
  
• api.ai-labs.conf
  
• blogs.ai-labs.conf
  
• f5exam.ai-labs.conf

ai-labs.co.conf file

    <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 ai-labs.co

            ServerAlias www.ai-labs.co
            ServerAdmin admin@ai-labs.co
            DocumentRoot /var/www/html/ai-labs.co/

            # 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

            # <Directory /var/www/html/web-api-example>
            # <Directory /var/www/html/music-store>
            <Directory /var/www/html/ai-labs.co>
                    Options Indexes FollowSymLinks
                    AllowOverride All
                    Require all granted
            </Directory>

            #Alias /static /var/www/html/web-api-example/static
            #Alias /static /var/www/html/music-store/static
            # <Directory /var/www/html/web-api-example/static>
            Alias /static /var/www/html/ai-labs.co/static
            <Directory /var/www/html/ai-labs.co/static>
                    Require all granted
            </Directory>

             <Directory /var/www/html/ai-labs.co/static>
                    Require all granted
            </Directory>

            Alias /static /var/www/html/ai-labs.co/media
            <Directory /var/www/html/ai-labs.co/media>
                    Require all granted
            </Directory>

            # <Directory /var/www/html/web-api-example/student_list_system>
            <Directory /var/www/html/ai-labs.co/ai_labs_website>
                    <Files wsgi.py>
                            Require all granted
                    </Files>
            </Directory>

            # WSGIScriptAlias / /var/www/html/web-api-example/student_list_system/wsgi.py
            # WSGIScriptAlias / /var/www/html/music-store/music_store/wsgi.py
            WSGIScriptAlias / /var/www/html/ai-labs.co/ai_labs_website/wsgi.py

    </VirtualHost>

I already did the CNAME where www is the name and @ is my hostname.

I really don't get it why the www subdomain just won't work