mail.g9.pt has no CNAME records.
Question and response
Question
dig mail.g9.pt. NS
Answer
The response has no answer records.
Authority
g9.pt. 174 SOA dns.nortenet.pt. hostmaster.nortenet.pt. 2026010201 86400 7200 3600000 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0