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gmail accounts no longer working in outlook classic

Ivan Glaser 15 Reputation points
2026-01-03T22:10:53.33+00:00

I have been using outlook to access my 4 gmail accounts for years. I use classic because I use SimplyFile to manage my emails. SimplyFile does not work in New Outlook

Two days ago the gmail connection stoppd working

Apparentlt google has changed authentication methods

Hos do I get it working again

Outlook | Windows | Classic Outlook for Windows | For business

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Ivan Glaser 15 Reputation points
2026-01-04T06:23:28.17+00:00

FYI, I run Windows as a VM. What I did was restore my VM from a backup I had 1 week ago. After restoring my VM, Outlook worked perfectly. This means that either a windows update or an Office update that got installed on Jan 1 made a change which caused gmail to stop working in outlook

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  1. Hornblower409 9,125 Reputation points
    2026-03-10T02:06:12.62+00:00

    Do these Support Articles apply in your case?

    Users get errors 0x800CCC0E & 0x800CCC0F synchronizing Gmail and Yahoo accounts in classic Outlook

    https://support.microsoft.com/en-us/topic/users-get-errors-0x800ccc0e-0x800ccc0f-synchronizing-gmail-and-yahoo-accounts-in-classic-outlook-e5a7b684-7c5c-4848-ab2d-d48291451f67

    Unable to add a Gmail account to classic Outlook

    https://support.microsoft.com/en-us/office/unable-to-add-a-gmail-account-to-classic-outlook-4d9530c5-3f40-4e6d-9b45-4477f160828f

    The article title is "Unable to add a Gmail account ..." but I have seen reports that this bug can also cause any IMAP accounts to fail. The fix is the same - Clear the Windows Credentials.

    If this is not your problem You might be better served by starting a new thread using the "Ask a question" button at the top of this page to create a new Question and include the details for your specific problem. This provides much higher visibility to your issue than commenting on an old post, which is only seen by people who are already following this question.

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  2. P. Dale Henson 0 Reputation points
    2026-03-15T16:47:24.7066667+00:00

    Hello, everyone, I just had to repair all of my Gmail Accounts in Microsoft Classic (I will use Classic until it no longer exists :) Here are the fixes: Outlook Classic and Gmail Sign-In / Credential Fix

    Use case: Gmail account in Outlook Classic would not add, showed IMAP or sign-in errors, or displayed “account needs attention.”

    Successful fix summary: The issue was caused by stale Outlook OAuth tokens in Windows Credential Manager and, in some cases, stale Microsoft permissions inside the Google account. Clearing those forced Outlook to create a fresh Google sign-in token.

    Steps:

    1. Turn on 2-Step Verification in the Gmail account.
    2. Create an App Password only as a fallback. Outlook may not use it if OAuth works.
    3. Open Control Panel > Credential Manager > Windows Credentials.
    4. Delete all entries that start with MicrosoftOffice16_Data:OAUTH2.
    5. Open Outlook Classic and add the Gmail account again.
    6. Approve the Google / Microsoft permission prompt when it appears.
    7. If Outlook says the account needs attention, go to Google Account > Third-party apps & services > Microsoft apps & services and remove access, then sign in again from Outlook.
    8. For Gmail IMAP accounts, set Root folder path to INBOX to avoid folder mapping and sync issues.

    Detailed steps:

    • Close Outlook Classic completely before changing credentials.
    • Open Control Panel > Credential Manager > Windows Credentials.
    • Delete every credential that begins with: MicrosoftOffice16_Data:OAUTH2
    • Do not delete your Outlook profile, PST, or OST files for this fix.
    • Open Outlook Classic and add the Gmail account again.
    • If Outlook prompts with a Google browser sign-in, approve Microsoft apps & services access to Gmail.
    • If the account connects successfully, Outlook is using OAuth. In that case, the App Password is not needed.
    • If Outlook shows a ribbon warning like “account needs attention” and the browser sign-in link fails, open the Gmail account in a browser, go to Google Account > Third-party apps & services > Microsoft apps & services, and remove access. Then return to Outlook and sign in again to generate a fresh token.
    • For Gmail IMAP accounts in Outlook, set Root folder path to INBOX.

    Short forum version:

    Fix that worked for me with Gmail in Outlook Classic: open Control Panel > Credential Manager > Windows Credentials and delete every entry that starts with MicrosoftOffice16_Data:OAUTH2. Then reopen Outlook and add the Gmail account again. When Google prompts, approve Microsoft apps & services access. If Outlook still says the Gmail account “needs attention,” go to your Google Account > Third-party apps & services > Microsoft apps & services, remove access, then sign in again from Outlook to force a fresh OAuth token. For Gmail IMAP accounts, set the root folder path to INBOX.

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  3. Austin-H 8,355 Reputation points Microsoft External Staff Moderator
    2026-01-04T04:14:37.62+00:00

    Hello Ivan Glaser
    Thank you for posting question to Microsoft Q&A Forum.

    According to this issue, please check with the answers given by Q&A Assist above - may I know when signing into Google account in classic Outlook, did it prompt a session by opening your browser for further authentication? If it did not, consider using App Password.
    Please try to add your accounts by creating a new Outlook profile - then use app password.
    Guide for creating new Outlook profile: https://support.microsoft.com/en-us/office/create-an-outlook-profile-f544c1ba-3352-4b3b-be0b-8d42a540459d

    I hope this is helpful. Please let me know if you have any further questions.

    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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  4. AI answer

    2026-01-03T22:11:01.56+00:00

    If your Gmail accounts have stopped working in Outlook Classic, it's likely due to changes in Google's authentication methods. Google has moved towards using OAuth for authentication, which may affect how you connect your Gmail accounts to Outlook.

    To resolve this issue, you should:

    1. Enable 2-Step Verification on your Gmail account if you haven't already. This is necessary for creating an app password.
    2. Create an App Password for Outlook. You can do this by going to your Google Account settings, selecting Security, and then App passwords. Choose the app and device you want to generate the password for, and follow the prompts.
    3. Use the App Password instead of your regular Gmail password when adding your Gmail account to Outlook.

    Make sure that IMAP is enabled in your Gmail settings as well, as this is required for Outlook to connect properly. You can enable IMAP by going to Gmail settings, selecting the Forwarding and POP/IMAP tab, and ensuring that Enable IMAP is selected.

    If you continue to experience issues, consider creating a new Outlook profile specifically for your Gmail accounts, as mixing account types can sometimes lead to problems.

    References:

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

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