When you send an email from Audience Republic there are 5 events that can happen between Audience Republic and the receiving server. These are tracked in the status column in the message report.
Sent - your message has been sent from Audience Republic, but has not yet been delivered
Delivered – the receiving server accepted the message
Bounce – the receiving server denied the message and the address sent to is suppressed by Audience Republic moving forward
Blocked – the receiving server denied the message and the address is not suppressed by Audience Republic moving forward
Deferred – the receiving server delayed acceptance of the message