_spf.exonet.nl has no CNAME records.
Question and response
Question
dig _spf.exonet.nl. NS
Answer
The response has no answer records.
Authority
exonet.nl. 3600 SOA ns1.exonet.nl. hostmaster.exonet.nl. 2026030501 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0