Since last night I am unable to view my forum while logged in. It was working perfectly fine and I haven't logged out or anything but suddenly when I refreshed the page. I can't see anything but a white page. For some users the site is working fine but for others and myself it isn't. If I clear cookies. I can view the site as normal as a Guest. But soon as I login I see nothing. I haven't installed anything since at least November or modified anything. Why is it working for some and not for everyone? Google chrome said its a error 500. Urgent fix needed thanks.