mail01.hrlearnings.com has no CNAME records.
Question and response
Question
dig mail01.hrlearnings.com. NS
Answer
The response has no answer records.
Authority
hrlearnings.com. 468 SOA ns63.domaincontrol.com. dns.jomax.net. 2025080601 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0