On our server running v1.9.3, when we create domains that contain an ä, dns does not work for them.
The DNS query returns with a SERVFAIL.
Here are example logs from /var/log/daemon.log for a query:
Apr 2 14:37:41 main named[893]: zone xn--XXX-backhusle-qzb.de/IN: loading from master file /home/ZZZ/conf/dns/XXX-backhäusle.de.db failed: bad name (check-names)
Apr 2 14:37:41 main named[893]: zone xn--XXX-backhusle-qzb.de/IN: not loaded due to errors.
All old DNS Domains with umlauts work (created ~2023-2024), but for testing I deleted and recreated a DNS Domain that has an ä and now it also does not work.
Still trying to find out what changed, but that might need insight into the code / database structure.