OOF messages are surpessed

[woelki]

Hey guys,

I'm facing some OOF notification issues at customer side. A customer of us has a single O365 tenant, but with 2 organizations in it. Both companies have a centralized mail routing and want use their local infrastructure to send outbound emails.

In general this works for sending emails, but we have now found an issue with OOF messages between two cloud mailboxes. If a cloud mailbox got OOF active and an On-Premise user sends a mail to the cloud MBX he successfully receives the MailTip in Outlook and the notification mail.

If a cloud user sends the mail (for sure for the first time) to the cloud mailbox with active OOF, he receives the MailTip in Outlook, but no notification mail!

I have tried to trace this in messagetracking and I see the mail heading to the hybrid server. But on the hybrid server I cannot find the mail with Get-MessageTrackingLog.

Any help for chasing this issue would be appreciated.

Kind regards,

Christian  

[#2 · Accepted solution]

Hey guys,

I guess I can answer this myself. For some reason I could not find the messages on the hybrid server, but on the still existing DAG. There I could find the message events DROP. There I found the reason for it. The messages have been dropped, because the internal OOF message has been sent to an "external" recipient.

Just to remember, the external recipient is an internal one. This is caused due to the complex connector and transport rule setup with centralized mail flow. We hoped that cloud to cloud messages will be kept in the cloud, but this is not the case. We will address this with Fasttrack, because we created the routing with them.

If anybody got similar issues with this, just ping me.

Kind regards,

woelki