mta1a1.sp.actionkit.com has no NS records.
NS records for this zone are defined at sp.actionkit.com.
NS records for this zone are defined at sp.actionkit.com.
Question and response
Question
dig mta1a1.sp.actionkit.com. NS
Answer
The response has no answer records.
Authority
sp.actionkit.com. 900 SOA ns-1821.awsdns-35.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0