_spf.atoracle.com has no CNAME records.
Question and response
Question
dig _spf.atoracle.com. NS
Answer
The response has no answer records.
Authority
atoracle.com. 883 SOA ns1.p201.dns.oraclecloud.net. hostmaster.oracle.com. 2025111302 10800 3600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0