Starting today, the Google Chrome browser is going to show a full-page warning whenever users are accessing an HTTPS website that’s using an SSL certificate that has not been logged in a public Certificate Transparency (CT) log or could be for other reasons too.
By doing so, Chrome becomes the first browser to implement support for the Certificate Transparency Log Policy. Other browser makers have also agreed to support this mechanism in the future, albeit they have not provided more details.
This new policy was first proposed by Google engineers in 2016, and was scheduled to enter into effect in October 2017, but was later delayed for 2018.
Refer to our troubleshoot guide for SSL certificate errors on google chrome.