API STATUS: REJECT
Message state 'rejected' means SendPro refuses to send the email. The reason for this is always because the recipient has been placed on the Recipient Filter. This filter keeps track of email addresses that have marked your emails as SPAM, or the address itself does not exist.
Sometimes a message is marked as unwanted / spam, or a recipient address does not exist. In these cases, receiving servers expect professional senders to stop sending messages. Failure to do so may lead to spam filtering or even blacklisting. To avoid such consequences, SendPro adds such addresses to the Recipient Filter. Any future messages to an address on the filter will not be sent (status Rejected).