ExchangePro: PowerShell timeout requires reboot daily (4329067)

Issue

We have successfully migrated 10,000+ mailboxes using Exchange Pro, however we still have many mailboxes to go and it seems the product is loosing it's PowerShell connection with O365 and requiring a server reboot daily. Is this a known issue with ExchangePro?

I see this error in the OS Event Viewer log

Submitted Pending Jobs
PowerShell queue has timed out!
System.Management.Automation.PSInvalidOperationException: The pipeline was not run because a pipeline is already running. Pipelines cannot be run concurrently

Solution

This error indicates the PowerShell service account is being throttled.

When was the last time your team requested to uplift the concurrent number of PS-PowerShell sessions with your cloud tenant support? Typically, the request to uplift the concurrent PowerShell sessions is only good for 3-6 months.

Please reach out to Microsoft Support and request the PowerShell concurrent sessions are uplifted to at least 20 sessions to allow for throttling to be eased.