Struggling to access HA on HTTPS

I have a RaspPi configured with Raspbien and have installed letsencrypt.

I can access HA on IP:8123 but not on https://domain.duckdns.org
I have forwarded port 443 to 8123 TCP/UDP on my router settings.

In Chrome i get:

This site can’t be reached

domain.duckdns.org unexpectedly closed the connection.
ERR_CONNECTION_CLOSED

home-assistant.log is showing various versions of this

2019-02-02 16:33:51 ERROR (MainThread) [aiohttp.server] Error handling request
Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.5/site-packages/aiohttp/web_protocol.py", line 275, in data_received
messages, upgraded, tail = self._request_parser.feed_data(data)
  File "aiohttp\_http_parser.pyx", line 523, in aiohttp._http_parser.HttpParser.feed_data
aiohttp.http_exceptions.BadStatusLine: invalid HTTP method

Any thoughts on troubleshooting please?

Show us your http: config from configuration.yaml (appropriately redacted).

Are you trying from within or from without your local network (use your mobile with wifi off)?

I’ve Googled this and it suggests something may be wrong with my configuration file. This is what it looks like

     http:
   base_url: https://domain.duckdns.org
   api_password: blabla
   ssl_certificate: /etc/letsencrypt/live/domain.duckdns.org/fullchain.pem
   ssl_key: /etc/letsencrypt/live/domain.duckdns.org/privkey.pem

Ah - ha

Apologies, couldn’t post the full info to start due to not being able to create a post with more than 2 links… and then my account was suspended for some reason for an hour or so.

Anyway, thanks for your response Tom. I have managed to resolve the issue!

What i needed to do was

sudo chmod 755 /etc/letsencrypt/live/
sudo chmod 755 /etc/letsencrypt/archive/

Solved the issue for me! Hope it helps someone else too.