mail1.comodogroup.com has no CNAME records.
Question and response
Question
dig mail1.comodogroup.com. NS
Answer
The response has no answer records.
Authority
comodogroup.com. 1823 SOA ns1.netim.net. hostmaster.netim.net. 2602260013 10800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0