Office 365 is experiencing difficulties resulting from a service update to some of their network infrastructure. This has resulted in delays in delivering and sending mail for Office 365 customers. In some cases, affected users may receive Non-Delivery Reports when sending email messages to or from Queen's email addresses.

Microsoft is aware of the issue and is in the process of restarting services and redirecting traffic to avoid the affected infrastructure. In addition, they are reverting the service update which they believe caused the degradation of their service.

As a result, Queen's is experiencing a high amount of external message traffic which is being queued on-prem, awaiting delivery to be accepted by Office 365. Once Microsoft has finished redirecting traffic to unaffected systems, mail will slowly begin to be delivered as the queues begin to empty.

Users expecting mail from external sources, should expect delays in receiving these message. If the message hasn't been received within 24 hours, ask for the sender to resend the message.

Users sending mail to external addresses may be subject to delays in their message being delivered. If you receive a Non-Delivery Report for a message you attempted to send, please try sending your message again at a later time.