External https access via duckdns but only on linux

Configuration
1

Hi there,

somehow I can connect to HA going to https://XXXX.duckdns.com but only on linux. On windows, independently from the browser, I get a 400: Bad Request error.

This is the relevant (I hope) section of my configuration.yalm:

homeassistant: 
  external_url: https://XXXX.duckdns.org
  internal_url: http://192.168.178.178:8123

http:
  base_url: https://XXXX.duckdns.org
  server_port: 8123
  ssl_certificate: /ssl/fullchain.pem
  ssl_key: /ssl/privkey.pem