cleanport.nl has no MX records.
Question and response
Question
dig cleanport.nl. MX
Answer
The response has no answer records.
Authority
cleanport.nl. 86400 SOA edns109.ultradns.com. domains.nortonlifelock.com. 2022032903 21600 7200 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0