Possibly, all sites like this sometimes have problems.
"is it fixed"
I refer the honourable member to the answer I gave earlier.
"why did it go wrong?"
Because it's a complex chunk of code, running on a complex web-server, with a massive back-end database. This site isn't like a 'normal' web site, the pages don't already exist, sitting in a folder waiting for your browser to load them.
The server receives thousands of page requests a day, and it generates the whole page for each request on the fly - when you click on a thread link the server has to go to the databases, retrieve all the posts in the thread, put them into a code template and create the page, specially for you. Imagine a few thousand people on the site at any one time, all doing the same thing, clicking from this page to that page, and you'll understand how complicated it all is.
From time to time something says 'that's it, I've had it with all this, I'm not going to do it any more' and the site gently collapses. Someone has to rush in and nurse it back online again, and we don't have a permanent staff on 24 hour stand-by. Not until you all pay us £10 a year to access the site. We think it's better not to ask you to do that, and to put up with the occasional glitch.