Gmail has stopped replicating

Hello Peter Everett,

I understand how frustrating it is when your inbox stops updating. This typically occurs when the secure connection (called an OAuth token) between Google and Microsoft becomes corrupted or loses a required permission. 

Fortunately, the fix is straightforward. Here are the steps to clear out the blocked connection and prompt that sign-in window to appear again so we can grant the right permissions: 

Step 1: Revoke Google Access 

1. Go to your Google Account settings in a web browser. 
2. Navigate to Security > Your connections to third-party apps & services. 
3. Select Microsoft apps & services and click Remove all access. 

Step 2: Clear Windows Credentials 

1. Open the Credential Manager from your Windows Start menu. 
2. Click Windows Credentials and scroll down to Generic credentials. 
3. Find and Remove any entries containing MicrosoftOffice16_Data:OAUTH2 and tp_google_imap_Oauth2. 

Step 3: Reconnect Outlook 

1. Open Classic Outlook and click Sign in via browser on the top bar (or re-add the account). 
2. Important: When the Google sign-in window appears, make sure to check the box to "Read, compose, send, and permanently delete all your email from Gmail".

I hope my explanation of the server connection error and the recommendations work for you to get your Gmail syncing smoothly again. Please don't hesitate to reach out if you need any further assistance! 

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.

Follow these steps in order for classic Outlook on Windows:

1. Update Outlook to a fixed build
   • In Outlook, go to File > Office Account > Update Options > Update Now.
   • Ensure Outlook is on a build that includes the Gmail fix:
     • Current Channel / Current Channel Preview / Beta Channel: Version 2404 (Build 17531.10000) or later.
     • Monthly Enterprise Channel: Version 2407 (Build 17727.10000) or later.
   • If Outlook is older, let Office update and then restart Outlook.
2. Verify IMAP is enabled in Gmail
   • In a browser, sign in to Gmail at Gmail.com.
   • Select Settings (gear icon) > See all settings.
   • Open the Forwarding and POP/IMAP tab.
   • Under IMAP Access, select Enable IMAP.
   • Select Save Changes.
3. Reset Microsoft access in your Google account
   • Close Outlook.
   • In a browser, sign in to your Google account at google.com.
   • Select your profile picture > Manage your Google Account.
   • Go to Security.
   • Under Your connections to third-party apps & services, select Microsoft apps & services.
   • Select See Details for Microsoft apps & services has some access to your Google Account.
   • Under Access you've given to Microsoft apps & services, select Remove all access, then Confirm.
4. Delete cached Google IMAP credentials in Windows
   • From the Windows Start menu, search for Credential Manager and open it (on Windows 10, open via Control Panel if needed).
   • Select Windows Credentials.
   • Under Generic Credentials, find entries starting with MicrosoftOffice16_Data:OAUTH2.
   • Expand each and hover over the name until the full name shows tp_google_imap_Oauth2.
   • For each Gmail-related entry with MicrosoftOffice16_Data:OAUTH2, select Remove. There are typically two per Gmail account.
   • (Optional, more precise) To avoid removing other Google IMAP credentials, map them using the identities under:
     • Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities
5. Reopen Outlook and let it re‑authenticate to Gmail
   • Start Outlook.
   • When prompted to sign in to Google, complete the sign‑in and consent screens in the browser window that opens.
   • Allow Outlook a few minutes to resync the mailbox.

If replication still fails after these steps, confirm again that Outlook is on one of the fixed builds listed above and re-run steps 3–4 to clear and re-establish the connection.

References:

• Unable to sign in or add a Gmail account to classic Outlook
• Unable to add a Gmail account to classic Outlook
• Fix problems connecting your Google account to the Microsoft Cloud
• Connected email accounts like Gmail and Yahoo not working in Outlook.com
• gmail accounts no longer working in outlook classic - Microsoft Q&A