554 Sending address not accepted due to spam filter:
When I send e-mail to: firstname.lastname@example.org
return this error:
Jul 12 15:49:46 mail postfix/smtp: 17A5A1D3012E: to=<email@example.com>, relay=server4.universonet.com.br[126.96.36.199]:25, delay=20, delays=0.05/0.01/1.2/18, dsn=5.0.0, status=bounced (host server4.universonet.com.br[188.8.131.52] said: 554 Sending address not accepted due to spam filter (in reply to MAIL FROM command))
What should be this?
How do I fix?