Hi @Pierre Brébec ,
When i tried to desactivate a mail box i have this message for all the mailboxes:
I read through the issue description but got a little confused about why you tried to disable mailboxes on Exchange 2010, provided that all mailboxes have already been migrated to Exchange Online. Did I misunderstand anything here?
Now i need to decomission the old exchange 2010 server.
Is this the last Exchange on-premises server in your environment and you are now attempting to decommission it and remove the hybrid deployment? If this is the main task now, it's recommended to follow the instructions in the blog below: Decommissioning your Exchange 2010 servers in a Hybrid Deployment. If your organization is maintaining the hybrid and there are some other Exchange presence on-premises, refer to: Best practices when decommissioning Exchange 2010.
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