smtp6.cashnet.com has no NS records.
NS records for this zone are defined at cashnet.com.
NS records for this zone are defined at cashnet.com.
Question and response
Question
dig smtp6.cashnet.com. NS
Answer
The response has no answer records.
Authority
cashnet.com. 300 SOA ns1-04.azure-dns.com. azuredns-hostmaster.microsoft.com. 1 3600 300 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0