smtp.fibertelecom.com has no CNAME records.
Question and response
Question
dig smtp.fibertelecom.com. NS
Answer
The response has no answer records.
Authority
fibertelecom.com. 3600 SOA ns.fibertelecom.com. noc.fibertelecom.it. 2025122023 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0