mxr.valueserver.jp has no NS records.
NS records for this zone are defined at valueserver.jp.
NS records for this zone are defined at valueserver.jp.
Question and response
Question
dig mxr.valueserver.jp. NS
Answer
The response has no answer records.
Authority
valueserver.jp. 1800 SOA gabriel.ns.cloudflare.com. dns.cloudflare.com. 2395926085 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0