Mail sending blocked by spamhaus.org

Mail sending blocked by spamhaus.org

Hi,


I was trying to send a mail but this mail delivery error:

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.


flavio@krieger.com.br Invalid Address, ERROR_CODE :554, ERROR_CODE :5.7.1 Service unavailable;
Client host [74.201.84.155] blocked using dnsbl.sorbs.net;
Currently Sending Spam See: http://www.sorbs.net/lookup.shtml?74.201.84.155