The requested URL was not found on this server.

Solved!

Thanks to everyone for the help. I managed to fix my problem with generating SSL keys and include them in my vhost configuration like this:

Code:

<VirtualHost *:443>
    DocumentRoot "${SRVROOT}/htdocs/example.com/www/"
    ServerName example.com

    SSLEngine on
    SSLCertificateFile "conf/ca.crt"
    SSLCertificateKeyFile "conf/ca.pem"
    <Directory "${SRVROOT}/htdocs/example.com/www/">
        Options All
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

also, I get an error for "Session: Configured save path '' is not a directory, doesn't exist or cannot be created.", that error is because of difference in OS. Locally I'm using Windows, so the solution for that issue is to change the sess_save_path option in config.php file. 

Code:

$config['sess_save_path'] = sys_get_temp_dir();

After that, I get another error ".htaccess: Invalid command 'Order', perhaps misspelled or defined by a module not included in the server". That error was because of the difference in Apache versions. The solution is to modify .htaccess file and replace this:
Order Deny,Allow
Deny from All
with:
Require all denied

But now I have another issue which exists in both my local site and my public one on the hosting server. The site is multi-language and when I click to switch on the English version I get Error 404 Page Not Found and I don't see something helpful in logs. Any help will be appreciated!!!