Outlook email keeps prompting for a password, and then not accept it. Blocked out of emails.

Anonymous
2025-01-23T06:50:57+00:00

Why does my Outlook email keep asking for a password, and then not accept it. This started today with a pop up window, and now after several restarts and password entries my Outlook will not open at all, so I cannot copy and paste the error message. Something seems to have changed since earlier in the day. I am using Outlook (not new, in Microsoft 365).

Outlook | Windows | Classic Outlook for Windows | For business

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  1. Anonymous
    2025-03-09T19:02:19+00:00

    We have a variety of versions of Outlook that are in use with Exchange Server 2019. All have same issue. Everything is on premise. No online accounts

    I've opened a support ticket on this. I'll post results.

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  2. Anonymous
    2025-03-09T17:24:31+00:00

    Because Microsoft has disabled passwords instead opting for a biometrics approach to secure online accounts.

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  3. Anonymous
    2025-03-03T15:40:44+00:00

    Have you checked the Application Log in Event Viewer for Outlook related information? I was able to find this as an informational event:

    The Exchange web service request GetAppManifests failed. The error code is 0.

    HTTP Response Code: 401

    Additional Error Message:

    An unknown internal error occurred. The error code is 80004005

    Have you seen these registry entries to try:

    Manually Reset Autodiscover & EWS Settings

    • Close Outlook.
    • Open Registry Editor (regedit).
    • Navigate to: 
        CopyEditHKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
    • Add (or modify) these DWORD (32-bit) Values:
      • ExcludeHttpsRootDomain = 1
      • ExcludeScpLookup = 1
      • ExcludeSrvRecord = 1
      • ExcludeHttpRedirect = 1
      • ExcludeSrvLookup = 1
      • ExcludeLastKnownGoodUrl = 1
      • PreferLocalXML = 1
    • Restart the PC and try signing in again.

    https://learn.microsoft.com/en-us/previous-versions/troubleshoot/outlook/unexpected-autodiscover-behavior

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  4. Anonymous
    2025-03-03T14:22:25+00:00

    I've tried both values for EnableADAL and it still gives the continuous prompts (including removing it). We don't have that value by default. I believe that is for Exchange Online. We run Exchange on premise. We set the value of EnableExchangeOnPremModernAuth=1. We enabled Modern Authentication on the server, but we disabled it on the mailboxes by policy because we found that Outlook cannot support a profile with more than one account if you have it enabled. We spent a long time with Microsoft support to finally figure that out. We did all this about a year ago, so it is not the cause.

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  5. Anonymous
    2025-03-02T17:17:30+00:00

    Some reason (I suppose from an older Microsoft article) the registry key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity - EnableADAL was set to 0. This key hadn't been changed manually before Outlook started choking. Maybe Outlook 365 was enabling modern authentication by default (which makes sense), and ignoring the key. Why it started paying attention to the key, I don't know.

    I set it to value = 1 and Outlook logged in immediately.

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    8 people found this answer helpful.
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