spf_c.oraclecloud.com has no CNAME records.
Question and response
Question
dig spf_c.oraclecloud.com. NS
Answer
The response has no answer records.
Authority
oraclecloud.com. 768 SOA n2-a1.aka-ns.net. hostmaster.oracle.com. 2026021304 7200 600 1209600 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0