DuckDNS + Let's Encrypt broken?

Configuration
1

Not sure what has happened but since upgrading to 78.X I can’t get SSL to work

configuration.yaml file :

http:
  api_password: !secret http_password
  base_url: https://xyz.duckdns.org:8123
  ssl_certificate: /ssl/fullchain.pem
  ssl_key: /ssl/privkey.pem

duckdns config entries:

{
  "lets_encrypt": {
    "accept_terms": true,
    "certfile": "fullchain.pem",
    "keyfile": "privkey.pem"
  },
  "token": "e001dbdd-333e-4ee9-a7b7-7239de099325",
  "domains": [
    "xyz.duckdns.org"
  ],
  "seconds": 600
}

and this is the error in the log

2018-09-20 19:15:05 ERROR (MainThread) [homeassistant.core] Error doing job: SSL error errno:1 reason: HTTP_REQUEST
Traceback (most recent call last):
  File "uvloop/sslproto.pyx", line 504, in uvloop.loop.SSLProtocol.data_received
  File "uvloop/sslproto.pyx", line 204, in uvloop.loop._SSLPipe.feed_ssldata
  File "uvloop/sslproto.pyx", line 171, in uvloop.loop._SSLPipe.feed_ssldata
  File "/usr/local/lib/python3.6/ssl.py", line 689, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: HTTP_REQUEST] http request (_ssl.c:841)

umm… any ideas anyone?