_spf.cyberfusion.nl has no MX records.
Question and response
Question
dig _spf.cyberfusion.nl. MX
Answer
The response has no answer records.
Authority
cyberfusion.nl. 3600 SOA nsauth0.cyberfusion.nl. hostmaster.cyberfusion.nl. 2020012300 14400 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0