smtp1.email.ap-singapore-1.ocs.oraclecloud.com has no NS records.
NS records for this zone are defined at ap-singapore-1.ocs.oraclecloud.com.
NS records for this zone are defined at ap-singapore-1.ocs.oraclecloud.com.
Question and response
Question
dig smtp1.email.ap-singapore-1.ocs.oraclecloud.com. NS
Answer
The response has no answer records.
Authority
ap-singapore-1.ocs.oraclecloud.com. 300 SOA ns1.p200.dns.oraclecloud.net. hostmaster.ap-singapore-1.ocs.oraclecloud.com. 20467 3600 900 31536000 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0