My gmail accounts are no longer syncing with outlook.

Question

They sync with IOS so i assume the problem is on the ms side. I use classic outlook. How to fix?

Answer 1

Hello

Many users seem to have this issue recently. Microsoft is still investigating this issue. The current workaround is published here: https://support.microsoft.com/office/users-get-errors-0x800ccc0e-0x800ccc0f-synchronizing-gmail-and-yahoo-accounts-in-classic-outlook-e5a7b684-7c5c-4848-ab2d-d48291451f67

Answer 2

For classic Outlook on Windows, recent Gmail sync failures are typically caused by authentication changes or IMAP/Google permission issues. Use these steps that match the documented issues and fixes:

1. Confirm Outlook build and recent fix

• A known issue with Gmail sign-in and sync in classic Outlook has been fixed in recent builds.
• Ensure Outlook is updated to a build that includes the Gmail fixes (for example, Current Channel Version 2404 or later, and for another issue Version 2412 Build 18324.20168 or later).
• In Outlook, go to File > Office Account > Update Options > Update Now to get the latest build.

2. Re-run Google consent for Outlook (permissions issue) If Gmail was added but no longer syncs or shows IMAP errors:

• In Outlook, if an error dialog appears for the Gmail account, look for a Retry link.
• Select Retry so Outlook opens a browser sign-in for Google again.
• During Google sign-in, ensure the box is checked for:
  • “Read, compose, send, and permanently delete all your email from Gmail.” under Select what Microsoft apps & services can access.
• Complete sign-in and return to Outlook; sync should resume.

3. Fix “browser or app may not be secure” / IMAP setup errors If Outlook shows errors like:

• “The browser or app may not be secure.”
• “We weren’t able to set up your Google account with IMAP. You may need to make changes to your Gmail settings.”

Then:

• Make sure Outlook is on a channel/build that includes the fix where sign-in opens in a separate browser window (for example, Current Channel Version 2404 Build 17531.10000 or later).
• If previously switched to an Insider channel as a workaround, use the documented registry method to switch back to Current Channel and then update Outlook.
• If the error persists, verify in Gmail settings (via a web browser) that IMAP is enabled, as the error can also occur when IMAP is disabled. Google is in the process of removing this control, but it still exists for some accounts. See Google’s guidance at Add Gmail to another email client.

4. Check for app password vs. Google app password If using app passwords for multi-factor authentication:

• Ensure the password configured in Outlook is a Google app password, not a Microsoft app password. Using the wrong app password type will prevent Gmail from syncing.

5. Re-add the Gmail account in classic Outlook (if needed) If sync still fails after updating and re-consenting:

• Open Control Panel > Mail > Email Accounts….
• Remove the problematic Gmail account.
• Select New, enter name, Gmail address, and password, and let automatic setup run.
• When the Google sign-in window appears, sign in and again ensure the Gmail permission box for “Read, compose, send, and permanently delete all your email from Gmail” is checked.

These steps address the documented causes where Gmail accounts stop working in classic Outlook due to authentication, IMAP, or permission changes on the Google/Microsoft side.

---

References:

• Unable to sign in or add a Gmail account to classic Outlook
• Unable to add a Gmail account to classic Outlook
• Troubleshoot Outlook email setup
• gmail accounts no longer working in outlook classic - Microsoft Q&A
• search for solutions another user has found - Microsoft Q&A