mail.estraspa.it has no CNAME records.
Question and response
Question
dig mail.estraspa.it. NS
Answer
The response has no answer records.
Authority
estraspa.it. 600 SOA dns01.estracom.it. gmarco.dns01.estracom.it. 2025072501 7200 1800 3600000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0