mail.opennameserver.org has no CNAME records.
Question and response
Question
dig mail.opennameserver.org. NS
Answer
The response has no answer records.
Authority
opennameserver.org. 10800 SOA ns1.domainers.de. hostmaster.internetwire.de. 2025092501 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0