smtp.lisbv.nl has no CNAME records.
Question and response
Question
dig smtp.lisbv.nl. NS
Answer
The response has no answer records.
Authority
lisbv.nl. 5433 SOA rz-ns-01.winsped.de. admin.winsped.de. 2020033016 21600 21600 864000 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0