ns1.sphere.ad.jp has no CNAME records.
Question and response
Question
dig ns1.sphere.ad.jp. NS
Answer
The response has no answer records.
Authority
sphere.ad.jp. 7895 SOA ns1.sphere.ad.jp. dns.sphere.ad.jp. 2026022001 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0