Outlook stopped working today!

June Wu 20 Reputation points
2026-11-12T18:26:35.23+00:00

Our Office365 Business email stopped working all of a sudden today, we cannot access our e-mailbox through Outlook app or online. Please advise what's going on,

Outlook | Windows | Classic Outlook for Windows | For business

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  1. AI answer

    2026-11-12T18:26:55.53+00:00

    If Outlook and Outlook on the web both stopped working at the same time, this can indicate a Microsoft 365 or Exchange Online service issue rather than a problem with the Outlook app on one device.

    For a business Microsoft 365 account, the supported checks are:

    1. Check whether more than one person in the organization is affected. If multiple users have the same problem, admins should check Microsoft 365 Service health status for Exchange Online.
    2. If the issue is limited to one device or one user, run the standard Outlook fixes:
      • Start Outlook in safe mode: press Windows key + R, enter Outlook /safe, and test whether Outlook opens.
      • If safe mode works, disable COM add-ins in File > Options > Add-Ins > COM Add-ins > Go, clear active add-ins, restart Outlook, and add them back one at a time.
      • Repair Microsoft 365 from Control Panel > Uninstall a program, right-click the Microsoft 365 installation, then select Change > Online Repair.
      • Create a new Outlook profile from Control Panel > Mail > Show Profiles > Add. Warning: removing a profile can also remove associated data files. If it is unclear whether the data files are backed up or stored on a server, do not remove the existing profile.
    3. Make sure Windows and Office are fully updated.
    4. If classic Outlook is still hanging or crashing, run the classic Outlook troubleshooter or Microsoft Support and Recovery Assistant on the same Windows PC where classic Outlook is installed.

    If mailbox access is failing in both Outlook and the browser for business mail, the first priority is to have an admin verify Exchange Online service health before spending time on local Outlook repair steps.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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