mail.ezisp.nl has no CNAME records.
Question and response
Question
dig mail.ezisp.nl. NS
Answer
The response has no answer records.
Authority
ezisp.nl. 7200 SOA ns.example.com. n.kuhnen.easynetworking.nl. 2026022601 10800 3600 604800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0