antispam.gigant.cz has no MX records.
Question and response
Question
dig antispam.gigant.cz. MX
Answer
The response has no answer records.
Authority
gigant.cz. 1800 SOA ns1.geetoo.com. hostmaster.geetoo.com. 45 1200 600 1209600 1800
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0