mailhost.ic3.com has no CNAME records.
Question and response
Question
dig mailhost.ic3.com. NS
Answer
The response has no answer records.
Authority
ic3.com. 1318 SOA lloyd.ns.cloudflare.com. dns.cloudflare.com. 2381591583 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0