smtp.josworld.com has no CNAME records.
Question and response
Question
dig smtp.josworld.com. NS
Answer
The response has no answer records.
Authority
josworld.com. 395 SOA ns1.josworld.com. postmaster.josworld.com. 2026030201 10800 3600 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0