o1.sendgrid1.itnint.com has no NS records.
NS records for this zone are defined at itnint.com.
NS records for this zone are defined at itnint.com.
Question and response
Question
dig o1.sendgrid1.itnint.com. NS
Answer
The response has no answer records.
Authority
itnint.com. 300 SOA ns1-06.azure-dns.com. azuredns-hostmaster.microsoft.com. 1 3600 300 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0