mail.comdataonline.com has no CNAME records.
Question and response
Question
dig mail.comdataonline.com. NS
Answer
The response has no answer records.
Authority
comdataonline.com. 3211 SOA dns.itline.it. admin.dns.itline.it. 2024112801 86400 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0