Ah, that would explain it!
If you update /etc/hostname and set the system hostname to the full domain name, and you should be okay from then on.
You may want to ensure the ‘default’ domain (which may be named something like /srv/srv-fde6n.localhost) is renamed at the same time.
Yep, I’m aware of that, and support for proxying and NAT will be coming when I rewrite sympl-dns, as there’s a few services which need to be able to override the typical IP address.