relay.codero.com has no CNAME records.
Question and response
Question
dig relay.codero.com. NS
Answer
The response has no answer records.
Authority
codero.com. 1206 SOA ns1.codero.com. hostmaster.codero.com. 2026021703 14400 3600 1209600 46200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0