mailforward.iomart.com has no CNAME records.
Question and response
Question
dig mailforward.iomart.com. NS
Answer
The response has no answer records.
Authority
iomart.com. 1538 SOA heracles.iomart.com. hostmaster.iomart.com. 2026022600 43200 1800 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0