You need to think about what you want your site to show up as, www.example.com or simply example.com. Make sure that in your general settings, under Settings → General, the version you want to show up is properly reflected:
You will also want to set this correctly in Google Webmaster Tools. Make sure to set up your site with Google Webmaster Tools and set the preferred domain, you can find this setting under Settings → Preferred domain:
Where you can set it:
Realisation on snbchf.com
We use only non-WWW version, which is better. We also have redirect from WWW to non-WWW version, which is good, too. We don’t have any problems here.