On-prem Public Folder access for migrated O365 mailboxes

Matt Pollock 246 Reputation points
2022-01-25T16:23:04.587+00:00

Hello,

I recently migrated a test mailbox from Exchange 2019 on-prem to Office 365 (Hybrid setup already in place)

I followed the steps in this guide to allow on prem public folder access to the migrated user.

https://learn.microsoft.com/en-gb/exchange/hybrid-deployment/set-up-modern-hybrid-public-folders

Everything looks OK as per the guide.

The O365 user can see the "Public Folders" menu item in Outlook, however when I expand the PF I get an authentication prompt.

The user creds don't work, the prompt comes back.

This behaviour is as per the note in the guidance:

168433-image.png

I don't understand why the migrated user cannot access the public folder structure.

The user AD account is still in scope of the AADConnect sync
The mailbox has a public folder mailbox assigned

Can anyone shed any light on this please?

Thanks

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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  1. Matt Pollock 246 Reputation points
    2022-04-04T15:33:12.31+00:00

    Picking this issue back up after a couple of months, still struggling with it.....

    The issue:

    Mailboxes migrated from on-prem (exch 2019) to O365 cannot access on-prem public folders once migrated.
    The public folders menu item exists in Outlook, but the O365 mailbox user receives a repeated credential prompt when trying to expand the folders.
    The steps outlined in this documentation have been followed:

    https://learn.microsoft.com/en-gb/exchange/hybrid-deployment/set-up-modern-hybrid-public-folders

    One prerequisite of the documentation however states that:

    ****"An Exchange Online, Microsoft 365, or Office 365 user must be represented by a MailUser object in the Exchange on-premises environment in order to access Exchange Server public folders. This MailUser object must also be local to the target Exchange Server public folder hierarchy."****

    This cannot be correct however, as any migrated mailboxes whereby the associated account still exists as an on prem AD account will be represented by a "RemoteMailbox" object in Exchange on-pre rather than a "MailUser".

    Not sure if this is the root cause of my issues but I could use some clarification if possible.

    Thanks

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