cannot set up gmail in outlook classic

Follow these steps on the affected PC to fix Gmail setup in classic Outlook.

1. Confirm Outlook is on a fixed build

• The Gmail/IMAP error is a known issue in classic Outlook that has been fixed in newer builds.
• In Outlook, go to File > Office Account and check the Version.
• For the “browser or app may not be secure” / IMAP setup issue, the fix is available starting with:
  • Current Channel: Version 2404 (Build 17531.10000)
  • Monthly Enterprise Channel: Version 2407 (Build 17727.10000)
• If the version is older, choose Update Options > Update Now, let Office update, then restart Outlook and try adding the Gmail account again.

2. If adding still fails with the IMAP error, use the Gmail/credential reset workaround This addresses the 0x800CCC0E and “We weren’t able to set up your Google account with IMAP” errors when Outlook’s stored Google permissions/credentials are broken.

Step 1: Remove Microsoft apps & services access in Gmail

1. Close Outlook completely.
2. Sign in to the Gmail account in a browser at google.com.
3. Select the profile picture > Manage your Google Account.
4. In the left menu, select Security.
5. Scroll to Your connections to third-party apps & services and select Microsoft apps & services.
6. Under Microsoft apps & services has some access to your Google Account, select See Details.
7. Under Access you've given to Microsoft apps & services, select Remove all access.
8. Confirm when prompted.

Step 2: Delete the Google IMAP credentials from Windows Credential Manager

1. From the Windows Start menu, search for Credential Manager and open it. (On Windows 10, it may be under Control Panel.)
2. Select Windows Credentials.
3. Under Generic Credentials, find entries starting with MicrosoftOffice16_Data:OAUTH2.
4. Expand each one and hover over MicrosoftOffice16_Data:OAUTH2 to see the full name. Identify those that include tp_google_imap_Oauth2 (these are the Gmail IMAP credentials).
5. For each Gmail-related MicrosoftOffice16_Data:OAUTH2 entry, select Remove. There are typically two per Gmail account.
   • If multiple Gmail accounts exist and only one should be removed, map them using the identities under: Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities in Registry Editor before deleting.
6. Re-add the Gmail account in Outlook
7. Start Outlook.
8. Go to File > Add Account and enter the Gmail address.
9. When the Google sign-in window opens in the browser, sign in.
10. On the permissions screen, ensure the checkbox is selected for:
    • “Read, compose, send, and permanently delete all your email from Gmail.”
11. Complete the sign-in and let Outlook finish the setup.
12. If automatic setup still fails

• Use manual setup as IMAP:
  1. In Outlook, choose File > Add Account.
  2. Enter the Gmail address, select Advanced options, and check Let me set up my account manually.
  3. Choose IMAP and enter the Gmail password or app password if required.
  4. If it fails, choose Change Account Settings and verify the IMAP/SMTP settings using the values from the email provider or the POP and IMAP server name reference.

After these steps, Outlook on the affected PC should be able to authenticate to Gmail and complete the IMAP setup, matching the behavior seen on the other computer.

References:

• Unable to add a Gmail account to classic Outlook
• Unable to sign in or add a Gmail account to classic Outlook
• Troubleshoot Outlook email setup