Certificate errors occur when there's a problem with a certificate or a web server's use of the certificate. Internet Explorer helps keep your information more secure by warning about certificate errors.
Most common reason for such security certificate error is that the certificates are valid for a certain period of time, and if your computer’s date is set to other than the correct date, there are high chances that you will
get this warning. If you see the Security Certificate error even after you correct the date, then either the certificate of the website has really expired as it had to be renewed from time to time, or the site is not trustable.
If you encounter a certificate error at a website you have visited before without errors, it's possible the website is not configured correctly. Try retyping the address you are using. It is also possible that the website's
certificate has expired and the owner or operator needs to contact the certification authority to renew the certificate in order to continue using it. This is a website related problem, and cannot be corrected in Internet Explorer or your browser.
These errors can see on those websites which is not trustable, so never ever put your important login id or password on such pages if you see the Security certificate error.