QCOW2 Appliance: BIND is not querying the configured nameservers

Steps to reproduce

  1. Install the latest UCS qcow2 appliance on qemu-kvm 1:3.1+dfsg-8+deb10u4. (qemu version is not important)
  2. Setup to use / as name servers.
  3. Setup email to use smtp server on local network. (This triggers DNS issues)

Details, posted on ownCloud’s forum, but they directed me here: