Symptoms
Consider the following scenario:
- You install Microsoft Exchange Server 2019 Cumulative Update 12.
- You enable Extended Protection by running the Exchange Server Extended Protection script.
- You configure the Hybrid agent from the Exchange Control Panel (ECP).
- You try to migrate any Microsoft Exchange 2019 mailbox from On-Premises to Online.
In this scenario, mailbox migration fails after you enable Extended Protection.
Resolution
To fix this issue, install Cumulative Update 13 or a later cumulative update for Exchange Server 2019.