docker-fsn1.ops.nic.at has no CNAME records.
Question and response
Question
dig docker-fsn1.ops.nic.at. NS
Answer
The response has no answer records.
Authority
ops.nic.at. 30 SOA sec1.rcode0.net. lir-tech.nic.at. 2026033831 10800 3600 604800 30
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0