ptr0.transip.nl has no CNAME records.
Question and response
Question
dig ptr0.transip.nl. NS
Answer
The response has no answer records.
Authority
transip.nl. 63 SOA ns0.transip.net. hostmaster.transip.nl. 2026022600 300 60 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0