by AndiS » Wed Dec 29, 2021 5:56 pm
In short, don't worry in this case.
A while ago, browser producers decided to amp up the warning that you get when a site does not have a valid certificate because users tended to ignore them before.
Certificates expire and most people nowadays have automated the process to renew them every few months or so. No idea why Matt has not found time to do it. I never maintained such a site so I cannot say how much fuzz it is.
As long as you do not use the same password on different sites and as long as you are sure you know the difference between a hobby forum and a banking site, you are on the safe side. But depending on your browser, it can be an annoyance.