When the Outbox folder displays a red error icon, this means that there are messages which Relenta wasn’t able to send. Usually this happens because the remote SMTP server returned an error.
These unsent messages are highlighted in red. Click on the message subject to display the actual error message returned by the SMTP server.
To resend the emails after the conditions causing the error were removed, check the box in front of a message highlighted in red, then click Resend.