smtp.cloudclusters.io has no NS records.
NS records for this zone are defined at cloudclusters.io.
NS records for this zone are defined at cloudclusters.io.
Question and response
Question
dig smtp.cloudclusters.io. NS
Answer
The response has no answer records.
Authority
cloudclusters.io. 1800 SOA meera.ns.cloudflare.com. dns.cloudflare.com. 2397925864 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0