How to solve a WWW/NonWWW Header Check: FAILED <p>I ran a duplicate checker for my website and got the following message</p> <blockquote> <p>WWW/NonWWW Header Check: FAILED Your site is not returning a 301 redirect from www to non-www or vice versa. This means that Google may cache both versions of your site, causing sitewide duplicate content penalties.</p> </blockquote> <p>Is this something that i should be worried about and if so how should i fix it ?</p>