mail1273.upsemail.com has no CNAME records.
Question and response
Question
dig mail1273.upsemail.com. NS
Answer
The response has no answer records.
Authority
upsemail.com. 2433 SOA shadowcat-i.ups.com. hostmaster.nowhere.null. 2023100519 21600 1800 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0