mail02.mail.esat-x.com has no MX records.
Question and response
Question
dig mail02.mail.esat-x.com. MX
Answer
The response has no answer records.
Authority
esat-x.com. 6400 SOA auth02.ns.esat.net. hostmaster.esat.net. 2026013001 28800 7200 604800 6400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0