[exim] Error in Exim 4.31

Good morning folks

I don´t have so much knowledge on EXIM, so I´m having some problems to send
email´s to some domains.

Exim version is 4.31

When I try to send the message I get this error message in reply

distino@??? : SMTP error from remote mailer after MAIL
FROM:<meu@???>:
host correio.yyy.com.br:
550 5.7.1 Email rejected due to sending server misconfiguration

What could possibly be wrong? Could you give me some ideas?

Att,
Paulo