user.76-237-236-186.users.net-rosas.com.br has no MX records.
Question and response
Question
dig user.76-237-236-186.users.net-rosas.com.br. MX
Answer
The response has no answer records.
Authority
net-rosas.com.br. 1800 SOA net-rosas.com.br. root.net-rosas.com.br. 2017053306 36000 900 604800 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0