Internet Explorer treats as fatal any Secure Socket Layer/Transport Layer Security (SSL/TLS) certificate errors that interrupt ...

Internet Explorer treats as fatal any Secure Socket Layer/Transport Layer Security (SSL/TLS) certificate errors that interrupt navigation (such as "expired," "revoked," or "name mismatch" errors). 

If you enable this policy setting, the user is not permitted to continue navigation.

If you disable this policy setting or do not configure it, the user may elect to ignore certificate errors and continue navigation.