spf.hornetsecurity.com has no CNAME records.
Question and response
Question
dig spf.hornetsecurity.com. NS
Answer
The response has no answer records.
Authority
hornetsecurity.com. 1603 SOA hank.ns.cloudflare.com. dns.cloudflare.com. 2397418553 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0