Created attachment 6838 error screen chrome is blocking access to docs.xfce.org because the certificate is only good for www.xfce.org and xfce.org. You can bypass this in firefox, but chrome enforces HSTS and won't allow you to go any further than their scary insecure screen. See the attached screenshots.
I think i fixed this one last month, docs.xfce.org uses letsencrypt too now. Peer name: docs.xfce.org Subject: /CN=docs.xfce.org Issuer: /C=US/O=Let's Encrypt/CN=Let's Encrypt Authority X3 Valid From: Wed Oct 19 19:16:00 2016 Valid Until: Tue Jan 17 18:16:00 2017