554 5.2.0 STOREDRV.Deliver.Exception:ObjectNotFoundException.MapiExceptionNotFound - NDR when users send mail in Exchange Online

 I had never heard of this before, so maybe this helps others.

After sending an e-mail you may receive a NDR 554 5.2.0 STOREDRV.Deliver.Exception:ObjectNotFoundException.MapiExceptionNotFound.

What this means is that there is something on in the users mailbox called "clutter".
I had to look this up in my OWA mailbox.

You will only see this option when you have "Focused Inbox" turned on.
The user itself could turn it off, but in many cases the user doesn't know how to or is out of the office or whatever.

So ofcourse this can be done with PowerShell:

First check to see the current setting

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Get-Clutter -Identity username@domain.nl RunspaceId : 2a09c611-03b6-4926-8293-c1692c3bcb00 IsEnabled : True MailboxIdentity : username@domain.nl Identity : IsValid : True ObjectState : New

As you can see the setting "Clutter" is revered to as "IsEnabled"

Then set the value to $False

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Get-Mailbox username@domain.nl | Set-Clutter -Enable $false RunspaceId : 2a09c611-03b6-4926-8293-c1692c3bcb00 IsEnabled : False MailboxIdentity : CN=username,OU=tenantname.onmicrosoft.com,OU=Microsoft Exchange Hosted Organizations,DC=EURPR10A003,DC=PROD,DC=OUTLOOK,DC=COM Identity : IsValid : True ObjectState : New