Exim - Sender verify failed - rejected RCPT

The messages are Exim identifying two problems with the incoming email (server - sender):

• The server is trying too many times within a given amount of time (hammering)
• The "to" address and mailbox does not exist

Most probably your server tries to verify the sender's email address and it finds that there is no such address. It is a good, albeit not foolproof, method to filter out unsolicited email.

In order to verify this, the exim server connects to the remote SMTP server from which the mail originates accordig to the "MAIL FROM" command. If the server can't be reached, or if it doesn't know about that particular email address, the delivery is denied.

So, the error message is initially given by the MX server of "e-mydomain.com.br". Your server, when it doscovers that the email is originated from a nonexistent address, denies the delivery.

For this, the exim config contains entries like this:

deny message = Sender verify failed
     !verify = sender

Check your config and if you see something like this, then the cause of the errors is that your server denies mails from addresses which can't be verified.

In this case, you probably don't want to change it. Like I said, it is a good thing to check the sender. Real-world senders do have a valid email address, anyway.