Google is deprecating Chrome’s trust in the Symantec certificate authority (including Symantec-owned brands like Thawte, VeriSign, Equifax, GeoTrust, and RapidSSL). Websites that fail to replace these certificates will result in site breakage in upcoming versions of major browsers, including Chrome, says Chrome security team.
All the websites using an SSL/TLS certificate from Symantec that was issued before June 1, 2016, it will stop working in Chrome 66. Chrome 66 has already been released to the Canary and Dev channels, meaning affected sites are already impacting users of these Chrome channels. If affected sites do not replace their certificates by March 15, 2018, Chrome Beta users will begin experiencing the failures as well.
According to Google, starting in Chrome 70, all remaining Symantec SSL/TLS certificates will stop working, resulting in a certificate error. The first Chrome 70 Beta release will be around September 13, 2018.
Here an example with Print24.de, with a certificate RapidSSL: