spool.mail.gandi.net has no MX records.
Question and response
Question
dig spool.mail.gandi.net. MX
Answer
The response has no answer records.
Authority
gandi.net. 1200 SOA dns0.gandi.net. hostmaster.gandi.net. 2026021801 900 900 1209600 1200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0