staging.iomart.com has no CNAME records.
Question and response
Question
dig staging.iomart.com. NS
Answer
The response has no answer records.
Authority
iomart.com. 3600 SOA heracles.iomart.com. hostmaster.iomart.com. 2026030300 43200 1800 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0