There was a problem last night which affected some people. Unfortunately tests done between last night and today will not be able to be reviewed but you will still see a score and a rank where applicable. The issue has now been resolved and future tests will be reviewable as per normal.
Sorry for the slight hiccup. The site is so busy at this time that we had to make changes to try to reduce server load and prevent it getting too slow. The changes caused the issue above but have now been fixed.
Thanks to everybody for reporting the issue.