and the reported fix solved them. In my case, nsd just stopped listening on IPv6 port 53 and came back after I added “port: 53” to nsd.conf. Maybe its random, but certainly inconvenient (difficult to identify for beginners)
I’ve literally just had this problem and in nsd.conf, it was binding to an autoconfiguration ipv6 address. I disabled autoconfig ipv6 in systemctl and rebooted which resolved my problem.