smtp01.srv.celeste.fr has no MX records.
Question and response
Question
dig smtp01.srv.celeste.fr. MX
Answer
The response has no answer records.
Authority
srv.celeste.fr. 3600 SOA ns1.celeste.fr.srv.celeste.fr. support.celeste.fr. 2025051201 3600 900 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0