I am currently having this issue and i am unable to resolve it The owner of apps.facebook.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. This site uses HTTP Strict Transport Security (HSTS) to specify that Firefox only connect to it securely. As a result, it is not possible to add an exception for this certificate. Learn more… Report errors like this to help Mozilla identify misconfigured sites apps.facebook.com uses an invalid security certificate. The certificate is not trusted because it is self-signed. The certificate is only valid for Daniel The certificate expired on Wednesday, September 06, 2006 7:31 PM. The current time is Friday, July 15, 2016 1:15 PM. Error code: SEC_ERROR_UNKNOWN_ISSUER