Unable to change mailbox permissions

Question

We have inherited a Hybrid Exchange environment. It consists of 1 on-prem Exchange Server (Version 15.0 ‎(Build 1473.3)) and M365. All the mailboxes have been migrated to M365 and ADSync is present to replicate to M365.

The issue we have is that even as a Global and Exchange admin in M365, we are unable to edit the permissions of any users mailbox. Doing this via the M365 admin centre just returns a message saying "Something Went Wrong." If we try it in Powershell we get a "User is not allowed to call" message.

We are trying to understand if this is an issue with M365 or we are trying to make the permission change from the wrong location?

In a hybrid environment where all mailboxes have been migrated, from where you should you make permission changes to a mailbox?  Is there something else we are doing wrong here?

Thanks

Answer 1

Hi,@Jimhex2024

Thanks for posting your question in the Microsoft Q&A forum.

Based on your description, you are currently in a hybrid environment. All permissions in an Exchange hybrid deployment are not assigned in EAC or Exchange online PowerShell.

You can refer to this link for details:https://learn.microsoft.com/en-us/exchange/permissions

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