spf1.spf.atom.com has no CNAME records.
Question and response
Question
dig spf1.spf.atom.com. NS
Answer
The response has no answer records.
Authority
atom.com. 859 SOA frank.ns.cloudflare.com. dns.cloudflare.com. 2397474527 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0