cust.trined.nl has no MX records.
Question and response
Question
dig cust.trined.nl. MX
Answer
The response has no answer records.
Authority
cust.trined.nl. 3600 SOA dnsauth1.tnoc.nl. noc.tnoc.nl. 2020081705 3600 600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0