Error code

Firefox SEC_ERROR_EXPIRED_CERTIFICATE

FIREFOXSEC_ERROR_EXPIRED_CERTIFICATE
Browser Error Code· An error code shown in a web browser when a page fails to load.

What it means

The server's certificate has expired and the connection cannot be secured.

How to fix it

  1. Check and correct your system clock if it is set to a wrong date.
  2. If the clock is correct the certificate is genuinely expired and the site owner needs to renew it.
  3. Contact the site administrator.

Not affiliated with Firefox. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.