Sometimes this error comes in firefox for secure web pages.
Secure Connection Failed An error occurred during a connection to calomel.org. The OCSP response is not yet valid (contains a date in the future). (Error code: sec_error_ocsp_future_response) The page you are trying to view can not be shown because the authenticity of the received data could not be verified. * Please contact the web site owners to inform them of this problem.
This is because the user’s computer’s date and time is wrong
So when this computer’s browser goes to a secure web page (https) with SSL certificate, browser checks the SSL certificate’s expiration date with the
user’s system time. If the computer’s date and time is wrong then browser says the above error.
Make sure your system’s time is updated