ns4.virtuaserver.com.br has no MX records.
Question and response
Question
dig ns4.virtuaserver.com.br. MX
Answer
The response has no answer records.
Authority
virtuaserver.com.br. 39600 SOA ns.virtuaserver.com.br. root.virtuaserver.com.br. 1771634257 28800 7200 604800 39600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0