The SSL certificate used by a W3SVC instance is not valid for today's date.
This means that the SSL certificate expired. This can also happen if say another computer generated the certificate at 1:00 PM and it was installed on another computer who's time is before 1:00 PM, i.e. 12:55. Therefore the certificate is not yet valid.
A certificate for a website on your server is expired. The server certificate for instance "(instance #)" has expired or is not yet valid. To find the instance that is causing this error go to the Internet Information Services MMC snap-in and look at the properties of each of your websites and look at your logging properties to see the instance # in the log extended properties.
This error appears when the system time on the certificate server is different to the client pc where the certificate is installed onto.
e.g. Certificate server set to 02/01/01 12:00:00
Client PC set to 02/01/01 11:48:00
The certificate won't be valid until it's server issue time.