Separate email domain and not work

[keffer]

I have a domain configured for hosting Web, and email is on another server in the company.

Already set up the domain in the MX entry pointing to the IP of the mail company.

But not conigo send email from another domain hosted on this server for the company

The slave domain is configured correctly and the transfer recevendo


EX config bind

....
                 IN NS ns1.domain.com.br.
                 IN NS ns.xxx.com.br.
                 IN MX 10 mail.domain.com.br.

domain.com.br. IN A 72.233.xx.xx
www IN A 72.233.xx.xx
mail IN A 189.56.xx.xx


What could be wrong?