_spf.emailcampaigns.net has no NS records.
NS records for this zone are defined at emailcampaigns.net.
NS records for this zone are defined at emailcampaigns.net.
Question and response
Question
dig _spf.emailcampaigns.net. NS
Answer
The response has no answer records.
Authority
emailcampaigns.net. 900 SOA ns-389.awsdns-48.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0