I need help logging in to Outlook desktop app

Cyrus Muir 30 Reputation points
2025-09-09T19:57:28.0766667+00:00

I am not able to log in using my email and password on the outlook desktop app. I can log into the web based outlook no problem but the desktop app is not working. I keep getting an error message i the desktop app. Can you please help?

Thank you,

Cyrus

Outlook | Windows | Classic Outlook for Windows | For business
Answer accepted by question author
Anonymous
2025-09-09T22:51:37.1266667+00:00

Hi @Cyrus Muir,

It's wonderful news that the issue has been resolved. I truly appreciate your effort in finding a resolution. I believe that many users may encounter similar issue, and your case could serve as a valuable reference for them.   

Therefore, I would make a brief summary of this post so that other forum members could easily find useful information here:  

Issue Description:  

Outlook desktop login fails, while Outlook Web Access authenticates successfully.

Assessment:  

Login failure is due to case sensitivity in the email address.

More information 

You can ensure the email address is entered with the exact casing used during account log in next time.

As other users may search for similar issues in this forum, your post and solution will be a helpful reference. If you found this helpful, consider voting or marking it as a solution to make it easier for others to find.

Thanks again for your contribution.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".  

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  1. Cyrus Muir 30 Reputation points
    2025-09-09T21:59:25.62+00:00

    i fixed it. my email was case sensitive (did not expect that) thank you!

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    1 person found this answer helpful.
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  2. Anonymous
    2025-09-09T20:42:40.1733333+00:00

    Hi @Cyrus Muir,

    Good day! Thank you for reaching out to Microsoft Q&A forum and sharing the detail.

    To ensure we provide the most accurate support, could you please send me the screenshot of error message that you're seeing? That will help narrow down the cause.

    In the meantime, you can try some suggestions to troubleshoot:

    1. Restart and update Outlook

    • Close Outlook completely.
    • Open Microsoft 365 Apps or Office, and check for updates.
    • Restart your PC and try logging in again.

    2. Clear Cached Credentials

    Sometimes old credentials cause login issues:

    • Open Credential Manager (search in Start).
    • Go to Windows Credentials.
    • Remove entries related to Outlook, MicrosoftOffice or your email domain.
    • Restart Outlook and try logging in again.

    {D923C263-CD2E-49F9-B13D-1DA410A46784}

    3. Repair Outlook

    • Go to Control Panel > Programs > Programs and Features.
    • Find Microsoft Office or Outlook.
    • Click Change > Quick Repair (or Online Repair if Quick doesn’t work)

    User's image

    Kindly let me know your responses to the above questions, and feel free to share any other details you think might help us resolve the issue.

    Please understand that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.  

    Look forward for your response. 

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".  

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

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