How do I reestablish the ability to send emails from a shared mailbox?

Hunter, Carolyn 0 Reputation points
2026-11-04T14:14:59.9933333+00:00

I lost the ability to send emails from a shared mailbox. I can read incoming emails, move them to folders and create emails using the shared mailbox address. But when I sent an email yesterday, I received an error email with this code: [0x80070005-0x000004dc-0x00000524].

Outlook | Windows | Classic Outlook for Windows | For business
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  1. Innocent Cyubahiro 0 Reputation points Independent Advisor
    2026-11-04T14:40:12.8766667+00:00

    Hello Carolyn,

    Thank you for providing the error message and explaining what happens when you use the shared mailbox.

    Since you can still read incoming messages, move emails between folders and compose messages using the shared mailbox address, I'd first like to check whether the issue is related to its sending permissions or Outlook itself.

    The error code you received, 0x80070005-0x000004dc-0x00000524, can occur when the required permission to send from a shared mailbox is missing.

    Could you try the following?

    1. Test sending from Outlook on the web

    This is a useful first check because it helps determine whether the problem also occurs outside your desktop Outlook application.

    1. Open Outlook on the web.

    Sign in with your usual work account.

    Open the shared mailbox and start a new message.

    Select the From field and choose the shared mailbox address.

    Send a test email to yourself.

    If the message sends successfully, the problem may be specific to Outlook on your computer.

    If you receive the same error, the shared mailbox permissions should be checked.

    1. Check the shared mailbox sending permissions

    If the problem also occurs in Outlook on the web, ask your Microsoft 365 administrator to verify your Send As permission.

    The administrator can check this in the Exchange admin center:

    Go to Recipients, then Mailboxes.

    Select the affected shared mailbox.

    Open Manage mailbox delegation.

    Find the Send As section.

    Confirm that your work account is listed. If it is missing, the administrator can add it and save the changes.

    Please note that Full Access allows you to open and manage a shared mailbox, but it does not automatically grant permission to send emails from its address.

    1. If sending works online but fails in Outlook

    Microsoft has documented an Outlook issue that can affect shared mailbox functionality and produce the same error code.

    You can review Microsoft's guidance here:

    Shared mailbox is not automatically refreshing for new email in Outlook.

    If the permissions are correct and the problem only occurs in Classic Outlook, the Outlook profile may need further attention.

    Carolyn, could you confirm whether you can send a message from the shared mailbox using Outlook on the web, or whether you receive the same error?

    Also, are you using Classic Outlook for Windows?

    Your answers will help identify the cause and determine the appropriate next step.

    Kind regards,

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  2. AI answer

    2026-11-04T14:16:20.5266667+00:00

    Test sending from the shared mailbox in Outlook on the web first: failure there points to mailbox delegation or provisioning, while success there limits the problem to Classic Outlook’s local configuration.

    1. Test outside Classic Outlook

    1. Open Outlook on the web with your normal work account.
    2. Open the shared mailbox and send a new test message using its address in From.
    3. Check the result:
      • Sending fails in both web and Classic Outlook: continue with the permission check below.
      • Sending works on the web: skip to Classic Outlook-only fixes.

    The error does not prove by itself that permission was removed; Microsoft has also documented the same error for certain corrupted Outlook profiles.^1^

    2. Have an administrator verify Send As

    Being able to read and organize the mailbox confirms Full Access, but Full Access does not permit sending. To send with only the shared mailbox address displayed, your account also needs Send As.^2^

    An Exchange administrator should:

    1. Open the Exchange admin center.
    2. Go to Recipients → Mailboxes.
    3. Select the shared mailbox.
    4. Open Mailbox permissions → Manage mailbox delegation.
    5. Under Send As, verify that your user account is listed.
    6. If it is missing, select Add, choose your account, and save.
    7. Allow the change to propagate, restart Outlook, and send another test message.

    These are the documented delegation controls for Full Access and Send As.^3^

    Also verify that the shared mailbox is not hidden from address lists. In Outlook desktop, Send As and Send on Behalf do not work when HiddenFromAddressListsEnabled is True, because Outlook needs to resolve the mailbox through the Global Address List.^3^

    3. If Send As is already assigned but web sending still fails

    Do not immediately repair the Outlook profile, because the web failure indicates the problem is not limited to Classic Outlook.

    As a provisioning fallback, the administrator can remove your Send As delegation, wait at least 15 minutes, add it again, wait for propagation, and retest. In one closely matching case, the permissions appeared correctly assigned in the admin interfaces but sending resumed only after delegation was reprovisioned; that case required a second remove/add cycle and another wait.^4^

    If reprovisioning does not work, the Microsoft 365 administrator should:

    • Check Microsoft 365 admin center → Health → Service health for an Exchange Online incident.
    • Open a Microsoft support request so tenant audit and Exchange transport logs can be examined. Those backend logs are needed to identify why apparently assigned permissions are not being honored.^4^

    4. Classic Outlook-only fixes

    If web sending works, first recreate the cached sender selection:

    1. Start a new message in Classic Outlook.
    2. Select From → Other Email Address → From.
    3. Select the shared mailbox from the organization’s Global Address List rather than typing the address.
    4. Send a test message.

    If it still fails, create a fresh Outlook profile:

    1. Close Outlook.
    2. Open Windows Control Panel → Mail → Show Profiles.
    3. Select Add, configure your work account, and allow the shared mailbox to appear.
    4. Start Outlook with the new profile and test again.

    Microsoft documented profile recreation as the repair for profiles left corrupted by a specific Outlook Version 2202 incident that produced this same NDR. That incident was fixed in 2022, so on other versions this is a desktop-only troubleshooting step—not confirmation that your profile has the same historical corruption.^1^

    References

    1. Shared mailbox is not automatically refreshing for new email in Outlook
    2. Shared mailboxes in Exchange Online
    3. Create a shared mailbox
    4. Send as rights removed from shared mailbox - Microsoft Q&A
    AI-generated content may be incorrect. Read our transparency notes for more information.

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