Apache2 keeps redirecting to default page

I've installed some software for users to be able to change their ldap password on they own named self service password on this path: /usr/share/self-service-password/htdocs.

In sites-enabled my configuration is as follows: (file named 000-default.conf)

<VirtualHost *:80>
    ServerName <IP>

    DocumentRoot /usr/share/self-service-password/htdocs
    DirectoryIndex index.php

    AddDefaultCharset UTF-8

    LogLevel warn
    ErrorLog /var/log/apache2/ssp_error.log
    CustomLog /var/log/apache2/ssp_access.log combined
</VirtualHost>

(same thing is "configured" at sites-available").

I've made sure this .conf file (000-default) is enabled by a2ensite, and made sure everything else is disabled, and restarted apache2.

However, When browsing to my IP:81 , it keeps redirecting me to Apache default welcome page under /var/www/html .

I'm trying to find a solution for it for the past 2 hours and couldn't find the reason behind it.

Thanks for anyone willing to assist.