mx2.zeelandnet.nl has no CNAME records.
Question and response
Question
dig mx2.zeelandnet.nl. NS
Answer
The response has no answer records.
Authority
zeelandnet.nl. 1496 SOA ns1.dfn.nl. hostmaster.dfn.nl. 2026030302 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0