Did you know that Microsoft invalided/stopped the use of security certificates with a RSA key length of less than 1024 bits? And they started doing this back in August 2012? No, we missed that security bulletin too. So we awoke to a broken website.
(it was the client PC which was broken, but everyone blames the website when they can’t get to it.)
We had deployed KB2661254 that is.
As this was an internal website, we were able to generate a new (larger) certificate fairly quickly.