ns1.codero.com has no CNAME records.
Question and response
Question
dig ns1.codero.com. NS
Answer
The response has no answer records.
Authority
codero.com. 4834 SOA ns1.codero.com. hostmaster.codero.com. 2026021703 14400 3600 1209600 46200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0