cloud4b.net has no MX records.
Question and response
Question
dig cloud4b.net. MX
Answer
The response has no answer records.
Authority
cloud4b.net. 300 SOA dns27.servidoresdns.net. hostmaster.servidoresdns.net. 2013010320 21600 3600 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0