ll of a sudden not able to log in to gmail through Outlook.

Question

ll of a sudden not able to log in to gmail through Outlook. It's been working fine for years. NOTHING has changed on my end. Tried all the obvious stuff posted online. VERY FRUSTRATING! Exploring other email options for our company Google!

Answer 1

Found the fix - If this just started happening today, there is also a known Outlook + Gmail Workspace issue where modern authentication fails until you clear the stored credentials in Windows.

 Clear Cached Credentials: Open Windows Control Panel, go to Credential Manager, select Windows Credentials, and delete all saved entries related to MicrosoftOffice16_Data:org.outlook.office.google.

 After I cleared out the credentials mentioned about I was able to add the account back to Outlook.

Answer 2

For classic Outlook on Windows, recent sign-in failures with Gmail are typically caused by changes on the Google side (authentication and IMAP controls) or by an Outlook build issue. Use these targeted checks and fixes:

1. Confirm IMAP is enabled in Gmail
   • In a browser, sign in to Gmail.
   • Select the gear icon > Settings.
   • Go to Forwarding and POP/IMAP.
   • Under IMAP access, select Enable IMAP.
   • Select Save Changes. If IMAP is disabled, Outlook cannot connect and you may see errors like “We weren’t able to set up your Google account with IMAP. You may need to make changes to your Gmail settings.”
2. Verify Gmail is exposing folders over IMAP Outlook needs the core folders to be visible via IMAP.
   • In Gmail, go to Settings again.
   • Open the Labels tab.
   • Ensure Show in IMAP is selected for Inbox, Sent Mail, Trash, and All Mail.
   • Optionally enable Show in IMAP for any other labels that should appear in Outlook.
   • Wait up to 15 minutes and then refresh Outlook.
3. Check Outlook’s Gmail server settings If using manual/IMAP setup in classic Outlook, confirm the Gmail server details match:
   • Incoming (IMAP):
     • Server: imap.gmail.com
     • Port: 993
     • SSL: Yes
   • Outgoing (SMTP):
     • Server: smtp.gmail.com
     • SSL: Yes; TLS/STARTTLS: Yes (if available)
     • Port for SSL: 465 or Port for TLS/STARTTLS: 587
     • Authentication: Required
   • Username: full Gmail address
   • Password: current Gmail password or app password (if using 2‑step verification)
   • On the IMAP details page in Outlook, ensure Require logon using Secure Password Authentication (SPA) is unchecked.
4. Recreate the Gmail account profile in classic Outlook (if password is never requested) If Outlook is not prompting for a password or keeps failing silently:
   • Open Control Panel > Mail.
   • Select Email Accounts….
   • On the Email tab, select New.
   • Enter name, Gmail address, and password (or app password) and select Next.
   • Complete the wizard and select Finish.
5. Make sure Outlook is on a fixed build for Gmail sign-in There have been known issues where Outlook’s sign-in flow to Google breaks and is later fixed in specific builds. For classic Outlook that shows errors like “The browser or app may not be secure” or fails to complete Google sign-in, install the Outlook build that includes the fix (for example, Version 2404 Build 17531.10000 in Current Channel and related channels). If an Insider Channel was used as a temporary workaround, switch back to Current Channel after updating.
6. If using connected Gmail in Outlook.com or Outlook on the web If the scenario is Outlook.com with a “connected account” to Gmail rather than direct IMAP in classic Outlook, be aware that Microsoft has removed the ability to connect new third‑party accounts and to sync existing connected accounts from Outlook.com. In that case, use one of these instead:
   • Add the Gmail account directly to Outlook for Windows or Outlook for Mac as an IMAP account.
   • Or configure forwarding from Gmail to an Outlook.com address.

If all of the above are correct and the issue persists across multiple Gmail accounts that previously worked, the most common remaining causes are:

• IMAP not enabled or folders not exposed in Gmail for one or more accounts.
• Incorrect password vs. required app password (when 2‑step verification is enabled).
• Outlook not yet updated to a build that contains the latest Gmail sign‑in fixes.

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References:

• Fix problems connecting your Google account to the Microsoft Cloud
• Troubleshoot Outlook email setup
• Unable to sign in or add a Gmail account to classic Outlook
• Prepare your Gmail or Google Workspace (formerly G Suite) account for connecting to Outlook and Microsoft 365 or Office 365
• Connected email accounts like Gmail and Yahoo not working in Outlook.com