getting database connection error if connect the site without www

Here is what I got from both sites:

http://filmloverss.com/

<!-- Dynamic page generated in 43.190 seconds. -->
<!-- Cached page generated by WP-Super-Cache on 2014-07-28 01:43:15 -->

<!-- super cache -->

http://www.filmloverss.com/

<!-- Dynamic page generated in 0.602 seconds. -->
<!-- Cached page generated by WP-Super-Cache on 2014-07-28 06:10:50 -->

<!-- super cache -->

WP super cache maybe the cause. Seems like it have different caches for non-www and www version.

If you don’t want to deal with it right now, just add a rewrite rule to redirect non-www to www

RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Ref: http://stackoverflow.com/questions/2015159/htaccess-redirect-for-non-www-both-http-and-https

Thank you so much! I removed the Wp Super Cache plugin with all setting files. Then re-enabled. So, it worked!