Is your raspberry serving sebbane.xyz and is /var/www/wordpress/ the webroot for that site? Response headers of sebbane.xyz seem to indicate that it’s running an IIS server, and not something on your raspberry (unless you have some kind of reverse proxy setup).
To explain what the CA server needs to see in order to verify your ownership of your domain:
--webroot mode will put a certain file in your webroot under /.well-known/acme-challenge/{random}. Let’s Encrypt then requests this file via HTTP, and verifies that it’s serving the correct challenge token. So in order to verify ownership you need to put the file on your actual web server under /.well-known/acme-challenge/{random}. If you’re using IIS, this might be easier using manual mode (or look into alternative clients).