mail.activecom.net has no NS records.
NS records for this zone are defined at activecom.net.
NS records for this zone are defined at activecom.net.
Question and response
Question
dig mail.activecom.net. NS
Answer
The response has no answer records.
Authority
activecom.net. 1800 SOA isaac.ns.cloudflare.com. dns.cloudflare.com. 2397206292 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0