I'm getting the following e-mail when i try to send a message:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  xxxxx@xxxxx.com.br
    SMTP error from remote mail server after RCPT TO:<xxxx@xxxx.com.br>:
    host pro-millenium.com.br [200.148.204.226]: 554 Service unavailable; Client host [209.200.250.85] blocked using sbl-xbl.spamhaus.org; http://www.spamhaus.org/SBL/sbl.lasso?query=SBL59864

------ This is a copy of the message, including all the headers. ------

Return-path: <xxx@csrbrasil.com>