This indicates that the certificate needs to be reissued. This is a result of the Browser distrust.
This error indicates the certificate for the site has been revoked. If you are the site owner you can contact the certificate issuer for further information as to why this might be.
Customers affected by the upcoming distrust of Symantec, Geotrust, Thawte and RapidSSL certificates have a number of options prior to the September deadline to ease the reissue process.
Information about how to replace your distrusted certificate
Information about the option to bulk reissue certificates affected by the Symantec distrust.