Can't login when using SSL/HTTPS

Hey all, having some trouble with a fresh install of Home Assistant OS. I’m trying to get SSL working so that I can use it with Google Assistant. All my port forwarding seems to be working correctly, because if I go to my-domain.duckdns.org I am able to view the login page. Once I log in, however, it hangs on the loading screen until I eventually can see a websocket error in the console:

core.7829e4bb.js:1 WebSocket connection to 'wss://my-domain.duckdns.org/api/websocket' failed: Error in connection establishment: net::ERR_CONNECTION_TIMED_OUT

Any ideas?

I’m using NGINX and DuckDns add-ons. Here’ my NGINX config:

domain: my-domain.duckdns.org
certfile: fullchain.pem
keyfile: privkey.pem
hsts: max-age=31536000; includeSubDomains
cloudflare: false
customize:
  active: false
  default: nginx_proxy_default*.conf
  servers: nginx_proxy/*.conf

And here’s my DuckDNS config:

lets_encrypt:
  accept_terms: true
  certfile: fullchain.pem
  keyfile: privkey.pem
token: <redacted>
domains:
  - my-domain.duckdns.org
aliases: []
seconds: 300

I’m able to login using the mobile app, but not in any browser. I’ve been searching for a solution for a while now and can’t seem to find any, so any help would be appreciated!