mail.temnet.pt.temnet.pt has no CNAME records.
Question and response
Question
dig mail.temnet.pt.temnet.pt. NS
Answer
The response has no answer records.
Authority
temnet.pt. 228 SOA dns101.ovh.net. tech.ovh.net. 2023080200 86400 3600 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0