Error when someone makes a wrong login...

I am getting the following error when someone makes a mistake in login. How can I fix it.

Looks like you've LDAP enabled, but your servers CURL isn't setup to properly support it (and maybe also missing LDAP module?). You can disable it within Extensions > Plug-in Manager and disable "Authentication - LDAP".

Thanks Kyle. It did not work with disabling "Authentication - LDAP". I tried disabling "Authentication - Gmail" (was on the line below but did not show up in screenshot above) and it did make the error go away.

However, in gmail plugin description; I get this warning;

Description
Handles User Authentication with a GMail or Googlemail account (Requires cURL)
Warning! You must have at least one authentication plugin enabled or you will lose all access to your site.

what does this mean? do I need to worry for it because I do have a gmail account registered at my Joomla as an admin.

All that plugin does is let users login to your site using their GMail account. It'll register them if they don't exist. You only need "Authentication - Joomla" enabled.