cannot add gmail account to Outlook Classic

Question

My gmail account has been in Outlook for a number of years and all of a sudden it stopped working I get an error message about IMAP which is the correct protocol not being valid

Answer 1

Hi, I'm John! I will help you with this.

Are you using Outlook Classic (desktop app)?

You can try the "Manual Workaround" provided in this Microsoft article:

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

Please follow the steps under "Manual Workaround" and then restart Outlook after completing them.

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I really hope this information is helpful! Let me know if you have any further questions or concerns.

Regards,

John J.D.

Answer 2

The IMAP error with a long‑working Gmail account in classic Outlook is a known issue related to recent changes in Google authentication and how Outlook connects to Gmail.

Use these steps that match the documented fixes and workarounds:

1. Confirm Outlook is on a fixed build

• The issue adding or syncing Gmail in classic Outlook is fixed starting with Current Channel Version 2412 Build 18324.20168.
• If Outlook is older, update Office, then try the Retry/sign‑in steps below.

2. Retry the Gmail browser sign‑in from Outlook

• When the IMAP error appears in Outlook, look for a Retry link in the error window.
• Select Retry so Outlook opens the Google sign‑in page in a browser.
• During Google sign‑in, ensure the permission box is checked for:
  • “Microsoft apps & services can access: Read, compose, send, and permanently delete all your email from Gmail.”
• Complete sign‑in and let Outlook resync.

3. If Retry does not work, use the manual workaround Follow the documented manual workaround to reset the Gmail/Outlook trust and credentials.

Step 1: Remove Microsoft apps & services access in Google

1. Close Outlook.
2. Sign in to the Google account at Google.com.
3. Select the profile picture > Manage your Google Account.
4. Go to Security.
5. Under Your connections to third-party apps & services, select Microsoft apps & services.
6. Under Access you've given to Microsoft apps & services, choose Remove all access, then Confirm.

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

1. Open Credential Manager from the Windows Start menu (or via Control Panel on some systems).
2. Select Windows Credentials.
3. Under Generic Credentials, find entries starting with MicrosoftOffice16_Data:OAUTH2.
4. Expand each and hover over the name to see the full value; identify those containing tp_google_imap_Oauth2.
5. Remove both credentials for the Gmail account (there are two per Gmail account).
   • If multiple Gmail accounts exist and only one is affected, the identities can be mapped using the registry path described in the article so only the correct credentials are removed.

Step 3: Sign in again from Outlook

• Reopen Outlook.
• If the Gmail account is still in the profile but not syncing, use the Sign in via browser banner in Outlook and sign in again.
• If the Gmail account was removed, go to File > Add account, add the Gmail address, and complete the browser sign‑in.
• During sign‑in, ensure the Microsoft apps & services Gmail permission box is checked as above.

4. Confirm IMAP is enabled and server settings are correct If errors still mention IMAP:

• In Gmail settings (on the web), verify IMAP is enabled under Forwarding and POP/IMAP (for accounts where this control still appears).
• Ensure Outlook is using the documented Gmail IMAP/SMTP settings:
  • Incoming (IMAP): imap.gmail.com, SSL required, port 993
  • Outgoing (SMTP): smtp.gmail.com, SSL/TLS required, authentication required, port 465 (SSL) or 587 (TLS/STARTTLS)

5. If prompted for an app password

• Some providers require an app password for IMAP in classic Outlook.
• If a message appears asking to create an app password for Outlook, follow the provider’s instructions to generate an app password and use that instead of the normal account password when Outlook prompts.

These steps address the known Gmail/IMAP breakage in classic Outlook by fixing Google permissions, clearing cached OAuth credentials, and re‑establishing the connection with the correct IMAP configuration.

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References:

• Unable to add a Gmail account to classic Outlook
• Unable to sign in or add a Gmail account to classic Outlook
• Fix problems connecting your Google account to the Microsoft Cloud
• Add an email account to Outlook for Windows
• Troubleshoot Outlook email setup