mail.cldin.eu has no MX records.
Question and response
Question
dig mail.cldin.eu. MX
Answer
The response has no answer records.
Authority
cldin.eu. 180 SOA ns3.cldin.eu. hostmaster.cldin.eu. 1771952607 3600 900 1209600 180
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0