spf.extole.io has no NS records.
NS records for this zone are defined at extole.io.
NS records for this zone are defined at extole.io.
Question and response
Question
dig spf.extole.io. NS
Answer
The response has no answer records.
Authority
extole.io. 900 SOA ns-231.awsdns-28.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0