These problems are intermittent and sporadic and we are working overtime to find a solution.
For some users, this may be because pages are ‘caching’ on your browsers and therefore showing older pages.
In that case, a page refresh will clear the error message you are seeing - press ctrl-f5 on a PC, cmd-R on a Mac.
Other users will need to clear their browser cache (no need to clear history or cookies, just the cache) and retry the page.
Thanks, as always, for your patience.