mail.dpgapi.dk has no CNAME records.
Question and response
Question
dig mail.dpgapi.dk. NS
Answer
The response has no answer records.
Authority
dpgapi.dk. 74 SOA ns01.one.com. hostmaster.one.com. 2026022303 14400 3600 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0