ns4.nasdns.net has no CNAME records.
Question and response
Question
dig ns4.nasdns.net. NS
Answer
The response has no answer records.
Authority
nasdns.net. 10800 SOA ns10.nasdns.net. nascloud.nadserv.com. 2025081501 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0