When I go to your site, all the links I click on go to yoursite.net. When I go to login and I press the button to login, the page the 'runs' is
www.yoursite.net and then it returns me to yoursite.net and I'm not logged in. If I go and add www in front of the url, then I am logged in. All the links that I see on your page (like the ones in the navbar) are to yoursite.net. I think you need to decide if you want to use
www.yoursite.net or just yoursite.net and then use htaccess to make sure that users who go to the wrong one get redirected to the correct one.
Also, on your splashscreen, the register button goes to
www.yoursite.net, but the Homepage button goes to yoursite.net