Did an upgrade from 23.7.x series to 24.1.y.
The upgrade happened in two steps, first to an intermediatory release: 24.1.3 and followed by another manual upgrade to 24.1.7. After reboot, Unbound DNS service failed to start.
A manual start helped to fix the problem.
Any ideas as to why this happened?
Maybe the listening interface is not up when Unbound tries to start?
Have you checked the system logs?
Nothing in the logs. tried re-booting the system again and Unbound service is up and running.