The maximum delivery threshold will soon be set to 3,600 messages per hour in Office 365; any emails sent to a mailbox exceeding this limit will receive a non-delivery report. This post describes how to detect mailboxes whose level of activity could lead to this situation.
How to trigger the sending of conditional reports
It is possible to generate reports based on specific conditions, such as the presence of certain items in mailboxes or the number of correspondents to whom a message has been sent. This article tells you how to do it.
Try Promodag Reports Free for 45 Days