When viewing an outgoing message or "sent mailing" that is still in the process of sending, you may see the term "Retry Recipients".
Retry recipients are recipients the system has already attempted to send to and the receiving server has returned some kind of message saying, essentially, "I can't accept this right now, try again later."
This message could be triggered because their servers are too busy, they have some kind of greylisting system where they don't take the email on the first attempt, or it could be that something is just down on that recipient's end.
WILL DELIVRA ATTEMPT THE RETRY RECIPIENTS AGAIN AUTOMATICALLY?
The number of retries from Delivra can vary, as we have some rules that are specific to different systems that govern how often retries happen. Generally, we retry until the email either goes through, get firmly rejected, or the campaign expires (typically 4.5 days).