The server's security certificate has expired

[vulcanised]

Or something like that is a message I seem to be getting very frequently lately.

Offered with "Accept" or "Reject" I wonder, should I really be bothered? It's come up on small websites and multinational companies.

[green granite]

Check your time and date are set correctly.

[vulcanised]

Done daily.

[Milo Minderbinder]

which websites?
if its the same one, maybe the cert has expired or been withdrawn

However the date issue would be my first place to look as well

[Saab Dastard]

I get some errors on website certificates where they are blocked by OpenDNS (e.g. 2o7.net), but they are not Expiry errors.

SD

[vulcanised]

The only site I can recall immediately was British Gas. Again from memory I think it may have always been on https sites.

[txdmy1]

yep, usually on https sites. Down to those that maintain them not renewing the certs when they should. Used to be 1 of my jobs where I used to work :)
Muppets probably don't diary the expiry dates.

[Saab Dastard]

usually on https sites
ONLY on https sites! Certificates are not required for non-secure (http) pages.

SD

[txdmy1]

we used to use them on our internal domains for http sites so that they mimiced what were https site in production. Just saved the hassle of setting up https stuff