smx.pair.com has no CNAME records.
Question and response
Question
dig smx.pair.com. NS
Answer
The response has no answer records.
Authority
pair.com. 1936 SOA ns1.pair.com. root.pair.com. 2024021447 30 900 604800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0