There are a couple next steps you can take to troubleshoot this.

Check if services are listening - You can use telnet to attempt to connect to an open port on a remote machine. For example:

telnet google.com 80

You can then use CTRL+c on Linux/Mac to exit out of the connection.

This will open a telnet connection to google.com on port 80 (the default http port). You'll see google's server return a prompt (waiting for a web browser to request a page). This same functionality can be used to check if your mail server is listening on the ports you think it is.

telnet mail.liderancadesaltoalto.com.br 25

The other possible reason for the error Outlook is giving you would be that the name it is being given is not resolving. mail.liderancadesaltoalto.com.br appears to be working properly. smtp.liderancadesaltoalto.com.br, however does not resolve (did you create a DNS record for this subdomain?)

Hi Ryanpq,

Thanks a lot for your answer, it really helped a lot.
Now its working!

But, only for learning, what a did, insert "submission inet n - n - - smtpd" in "master.cf" was right?
Its necessary? Or just create de smtp DNS record was enough?

Once again, thanks a lot!