01-09-2021 08:41:00 AM (BST)
Issue Reported: 31/08/2021 02:45:00 PM
Microsoft Reference : EX282101
Issue Status: RESOLVED
Issue Description: Users may experience delays of up to two hours when sending email from on-premises to Exchange Online.
Scope of impact: This issue may affect any on-premises users sending email to users hosted in Exchange Online.
Final Update – 01/09/2021 08:45:00 AM: Microsoft have determined that an outbound traffic rule intended to exclude high volume senders from traffic management activities was inadvertently overwritten. As a result, email messages sent from on-premises users to Exchange Online users were throttled and queued for delivery. Microsoft has reverted the rule and confirmed with affected users that email is no longer queuing and queued email messages have been delivered.