mail.spf.ecritel.net has no CNAME records.
Question and response
Question
dig mail.spf.ecritel.net. NS
Answer
The response has no answer records.
Authority
ecritel.net. 60 SOA ns-a.ecritel.fr. postmaster.ecritel.fr. 2026030603 14400 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0