filter01.nedlook.com has no CNAME records.
Question and response
Question
dig filter01.nedlook.com. NS
Answer
The response has no answer records.
Authority
nedlook.com. 123 SOA ns3.esmero.nl. support.esmero.nl. 2023071301 10800 1800 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0