mta.gva.es has no CNAME records.
Question and response
Question
dig mta.gva.es. NS
Answer
The response has no answer records.
Authority
gva.es. 300 SOA ninot.gva.es. admincorreo.gva.es. 2026030502 14400 300 604800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0