That link is never going to work:
~ $ curl -vvvv https://groob.io/posts/go-sysadmin
* Trying 107.170.65.25...
* TCP_NODELAY set
* Connected to groob.io (107.170.65.25) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
* Server certificate: groob.io
* Server certificate: Let's Encrypt Authority X3
* Server certificate: DST Root CA X3
> GET /posts/go-sysadmin HTTP/1.1
> Host: groob.io
> User-Agent: curl/7.51.0
> Accept: */*
>
< HTTP/1.1 301 Moved Permanently
< Content-Length: 185
< Content-Type: text/html
< Date: Thu, 15 Dec 2016 21:16:14 GMT
< Location: http://localhost/posts/go-sysadmin/
< Server: Caddy
< Server: nginx/1.9.15
<
Caddy seems to be slightly misconfigured, localhost is quite a different host for me :).