mail.copernica.nl has no MX records.
Question and response
Question
dig mail.copernica.nl. MX
Answer
The response has no answer records.
Authority
copernica.nl. 60 SOA dns1.proxi.nl. hostmaster.copernica.com. 1771487630 14400 1800 86400 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0