mail01.jtglobal.com has no CNAME records.
Question and response
Question
dig mail01.jtglobal.com. NS
Answer
The response has no answer records.
Authority
jtglobal.com. 52 SOA ns0.jtibs.net. ops.jtibs.net. 2026022400 7200 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0