Can't open Shared mailbox on mobile device, works on every other client.

Anonymous
2021-06-15T13:20:37+00:00

We want to share mailboxes with 'Least privilege' principle.

So when creating a shared mailbox instead of making users Owner we want to assign only permissions on the necessary folders.

With a PowerShell session to Exchange Online we make the following changes:

Add-MailboxFolderPermission -Identity SharedMailboxTest:\ -user ******@contoso.com -AccessRights Reviewer

Add-MailboxFolderPermission -Identity SharedMailboxTest:\Inbox -user ******@contoso.com -AccessRights Reviewer

This works fine with Outlook Web App and Outlook desktop client. We can add the shared folder and read the messages.

But when we try to add a shared folder on a Outlook Mobile client we get an error:

Authentication failed

That didn't work. You may not have the right permissions to add this mailbox or this mailbox doesn't exist.

Also added permission directly on the mailbox:

Add-MailboxPermission -Identity SharedMailboxTest -User ******@contoso.com -AccessRights ReadPermission

But that didn't make a difference.

It must be possible to delegate folder permissions. It works for default clients, but it refuses to work on mobile Outlook unless I give the user Owner permissions, but that is not 'Least privilege'.
What I'm I missing here or did I stumble on a bug in Outlook Mobile?

(It has to be Outlook mobile client on cell phones)

Outlook | Windows | Classic Outlook for Windows | For home

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  1. Anonymous
    2021-09-15T12:12:43+00:00

    Working now, thank you Microsoft for the fix.

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  2. Anonymous
    2021-09-15T12:12:42+00:00

    I have still the sane problem. I am not able to connect 1 specific shared mailbox.

    Other shared mailboxes have no problem.

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  3. Anonymous
    2021-09-15T11:55:55+00:00

    We are still experiencing the same on iOS Devices. Some work, some don't, I have no clue why. All are using the latest ios outlook app?

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  4. Anonymous
    2021-09-15T06:39:39+00:00

    We have the same problem. It’s really important to solve it, since still doesn't work today.

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  5. Anonymous
    2021-09-14T08:10:24+00:00

    Unfortunately not working here, yet.

    Worked to add a shared mailbox a few weeks ago:

    iPadOS

    Now we also wanted to add this mailbox to an iPhone with most recent iOS and Outlook for iOS 4.2135.1 but the authentication error applies.

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