_spf.linkbymail.fr has no CNAME records.
Question and response
Question
dig _spf.linkbymail.fr. NS
Answer
The response has no answer records.
Authority
linkbymail.fr. 900 SOA amrns1501.accenture.com. dnsadmin.accenture.com. 6 10800 3600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0