casa-gw.gransy.com has no MX records.
Question and response
Question
dig casa-gw.gransy.com. MX
Answer
The response has no answer records.
Authority
gransy.com. 1800 SOA ns1.anycastdns.cz. root.gransy.com. 2772112861 86400 900 1209600 1800
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0