E-mails received by the SMTP receiver of the appliance are first processed in the mail processing queue.
This is where, for example, the spam check or the e-mail encryption takes place.
All e-mails that have to be forwarded by the SMTP sender of the appliance are processed in the delivery queue.
In both queues, the ID of the message, the time of receipt, sender, recipient, subject and size are displayed.
In the Mail Processing Queue, the Status tab shows the processing status of the e-mail.
The Delivery Queue offers instead the display of the last and next delivery attempts (if the delivery was not successful), the reason for the unsuccessful delivery and a counter for the number of delivery attempts.
If the cause of the unsuccessful delivery has been resolved (e.g. after a failure of the internal e-mail server), you can also manually click on Deliver again here.
Otherwise, the appliance attempts delivery in an interval