I’m posting this here since many community members are probably using duckdns.org.
It looks like ns1.duckdns.org is serving old information. I’ve tried querying ns1, ns2 & ns3.
ns1 will not update it’s records and will serve old records (also if you create a new domain it will not answer for it).
Didn’t find many references to this, but one is here:
https://news.ycombinator.com/item?id=22002625
I’m posting this mainly to let you know that if you have a problem don’t try to fix it, it will be fixed when ns1 is working again.
If someone have more info please share.