Logged out when I go to the non-www version of the domain
 

Hi folks,

I know I should be able to fix this, I've seen it asked a few times before.

When I log into my forum, everything is fine. When I remove the www. from the domain, I am logged out. I was sure it was something to do with the whitelist but I have added the domain (including the leading dot) but it's still the same.

Any ideas please? Thanks! :)