cust.vodafone.cz has no MX records.
Question and response
Question
dig cust.vodafone.cz. MX
Answer
The response has no answer records.
Authority
cust.vodafone.cz. 900 SOA ns2.vodafone.cz. ns-admin.vodafone.cz. 23 10800 3600 1209600 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0