The search box would not show up for me at all about six weeks ago so I used the contact form on the website and the webmaster there was very helpful.
Turns out that the site did not like one of the extensons I have for my browser, an adblocker, which I just leave activated most of the time. Not sure why it was that as they do not have adverts on their website anyway. When I disabled it just for Archives everything worked fine.
If you have any extensions or add-ons, try disabling them for the Archives site and see if that works.
Ian C