Yesterday, I've installed longview in my Linode, and seeing 80 packages needed to be updated, I ran aptget dist-upgrade.

Everything works fine with my Wordpress blog, except suddenly people can't access the homepage, and only if www is missing. The error message is:

"Error establishing a database connection"

Where it gets even more strange is that http://www.cnx-software.com works, but there's only a connection issue with http://cnx-software.com.

I can't see any message in /var/log/mysql/error.log, /var/log/nginx.log, nor /var/log/php5-fpm.log. There does not seem to be any error messages in the site specific error log either.

I guess dist-upgrade may have changed some config files, but I'm not exactly sure what to look for.

Just a hunch, but check the .htacess file in the wordpress directory. Then check the vhosts in /etc/apache2/sites-available (if you're using apache)

Cloudflare has cached your error page. Presumably they provide a way to clear that cache.

Thanks. Good idea, but I've just cleared the Cloudflare cache for the page, and even disabled CloudFlare a few hours ago, but the result is the same when connecting directly to my linode.

That's very strange because my DNS is supposed to redirect cnx-software.com to www.cnx-software.com. It works fine with anyother pages, but I'll get the database connection error, before redirection occurs.

You were right about the cache, but it's my cache plugin (Quick Cache) which did that. Thanks!