mail4.asipay.com has no NS records.
NS records for this zone are defined at asipay.com.
NS records for this zone are defined at asipay.com.
Question and response
Question
dig mail4.asipay.com. NS
Answer
The response has no answer records.
Authority
asipay.com. 3600 SOA ns6a.savvis.net. dns-admin.centurylink.com. 2220507020 3600 1800 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0