mx.mail.tiscomhosting.nl has no CNAME records.
Question and response
Question
dig mx.mail.tiscomhosting.nl. NS
Answer
The response has no answer records.
Authority
tiscomhosting.nl. 1233 SOA ns1.tiscomhosting.nl. hostmaster.tiscomhosting.nl. 2024091600 7200 3600 2419200 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0