chromium-browser: ERR_CERTIFICATE_TRANSPARENCY_REQUIRED
Chromium browser (53.xxx) no longer trusts Symantec and a lot of other issued certificates.
Workaround: add —ignore-certificate-errors
See:
https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1641380
Fixed in 54.xx
(from redmine: issue id 6460, created on 2016-11-15)