sysorb.netgroup.dk has no CNAME records.
Question and response
Question
dig sysorb.netgroup.dk. NS
Answer
The response has no answer records.
Authority
netgroup.dk. 3482 SOA authns1.ngdc.net. hostmaster.ngdc.net. 2026022203 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0