spf.20i.com has no NS records.
NS records for this zone are defined at 20i.com.
NS records for this zone are defined at 20i.com.
Question and response
Question
dig spf.20i.com. NS
Answer
The response has no answer records.
Authority
20i.com. 300 SOA ns1.stackdns.com. hostmaster.stackdns.com. 1709891269 1800 900 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0