Duckdns integration not working in config.yaml

When I add


http:
   base_url: MYDOMAIN.duckdns.org:8123 
   ssl_certificate: /ssl/fullchain.pem
   ssl_key: /ssl/privkey.pem

in the configuration.yaml file and reboot,
Home assistant is not starting anymore.

I am using Rpi3 . I have my port forwarding set up correctly, The router gives my homeassistant a fixed IP. When i use my IP, i can connect to it over my home network.
Duckdns is not working without the http: in the configuration.yaml file as well.

Also i tried to get the nginx server runnut that one always gives an “internal error” when trying to save the settings.
any idea’s?
I followed the steps of JuanMTech as much as i could do, but i have also no possibility to set incoming URL under “configuration/general”

thanks for the feedback already!