a2ensite error "Site not exist" when creating virtualhost apache2 on ubuntu

I have created files for my site in the /home/junda/www/ directory. I use symfony2, means the public files goes to /home/junda/www/symfony2-tries/web/ directory.

I then type this following command to the terminal to change permission:

sudo chmod -R a+rX ~/www
sudo chmod a+rx ~

I also create /etc/apache2/sites-available/symfony2-tries.com file with following content:

# domain: symfony2-tries.com
# public: /home/junda/www/symfony2-tries.com/

<VirtualHost *:80>

  # Admin email, Server Name (domain name) and any aliases
  ServerAdmin [email protected]
  ServerName  www.symfony2-tries.com
  ServerAlias symfony2-tries.com


  # Index file and Document Root (where the public files are located)
  DirectoryIndex app.php
  DocumentRoot /home/junda/www/symfony2-tries/web


  # Custom log file locations
  LogLevel warn
  ErrorLog  /home/junda/www/symfony2-tries/log/error.log
  CustomLog /home/junda/www/symfony2-tries/log/access.log combined

</VirtualHost>

after that i tried to enable it using a2ensite.

sudo a2ensite symfony2-tries

but it returns:

ERROR: Site symfony2-tries.com does not exist!

Could anyone kindly told me where I did wrong? And if possible, how to correct it. Thank You very much.

I have found the solution!

All files in /etc/apache2/sites-available/ must have the .conf extension now.

Example: symfony2-tries rename it in symfony2-tries.conf

Type sudo a2ensite symfony2-tries.conf and restart apache.