O365: On-Premises Transport Queuing Lessons Learned from CBL

I recently had a case where on-premises Transport had Queues that were ‘stuck’ going to the cloud. Specifically, they were going to Exchange Online Protection for routing from on-premises to cloud mailboxes. The on-premises transport servers were generating errors, in a unique way. For example, this is what we saw from the Queues in PowerShell:…

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