mail.redosk.eu has no CNAME records.
Question and response
Question
dig mail.redosk.eu. NS
Answer
The response has no answer records.
Authority
redosk.eu. 853 SOA dns17.ovh.net. tech.ovh.net. 2026021703 86400 3600 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0