d.ns.ns247.net has no CNAME records.
Question and response
Question
dig d.ns.ns247.net. NS
Answer
The response has no answer records.
Authority
ns247.net. 2560 SOA a.ns.ns247.net. hostmaster.ns247.net. 2019042501 16384 2048 1048576 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0