Slow when accessing via public URL

Configuration
1

Hi, I just got my SSL set up working with let’s encrypth and asus ddns service… When I access my HA via https://192.168.xxx.xxx (local) it is super fast as expected but when I go via my public URL it so slow so that the UI barely loads and the iOS app can´t connect at all

This is my http config from configuration.yaml

http:
  ssl_certificate: /ssl/fullchain.pem
  ssl_key: /ssl/privkey.pem
  use_x_forwarded_for: True
  trusted_proxies:
   - 192.168.72.1

Any clues?

BR.,
Lars