cldin.net has no MX records.
Question and response
Question
dig cldin.net. MX
Answer
The response has no answer records.
Authority
cldin.net. 3600 SOA ns1.cldin.eu. hostmaster.cldin.net. 1772332698 3600 900 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0