smtp4.digitalmailer.com has no NS records.
NS records for this zone are defined at digitalmailer.com.
NS records for this zone are defined at digitalmailer.com.
Question and response
Question
dig smtp4.digitalmailer.com. NS
Answer
The response has no answer records.
Authority
digitalmailer.com. 1800 SOA ivan.ns.cloudflare.com. dns.cloudflare.com. 2398529066 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0