New Outlook Can’t Add Gmail Account: Fix the Authentication Loop

You add your Gmail address to the new Outlook, a Google sign-in window opens, you sign in… and Outlook drops you straight back where you started. Or it adds the account and then says authentication failed. Or — the most annoying version — it works, but asks you to do the whole Gmail authentication again every time you run the app.

Almost all of these have the same root: the new Outlook never sees your Gmail password at all. Google retired password-based sign-in for third-party mail apps, so the new Outlook connects through a browser sign-in (OAuth): Google checks your password and 2-Step Verification itself, then hands Outlook a token. When that handoff breaks — the Allow step never completed, an old token grant went stale at Google, or Windows is holding a dead saved credential — the app loops, fails, or re-asks forever.

If new outlook can’t add gmail account, the fixes below repair the handoff, in order.

Quick Answer: Add the account via Settings > Accounts > Your accounts > Add account, choose the Google sign-in, and complete the browser sign-in, clicking Allow for “Microsoft apps and services” (Fix 1). If it loops or re-asks at every launch, go to your Google Account’s third-party access page, remove “Microsoft apps and services” access, then re-add the account (Fix 2). Still stuck? Delete stale Google entries in Credential Manager (Fix 3) and confirm IMAP is enabled in Gmail’s settings (Fix 4). App passwords are for Classic Outlook only — they do not work in the new app.

Why Gmail Sign-In Fails in the New Outlook (OAuth, Not Passwords)

In Classic Outlook, adding Gmail historically meant typing server names — and, later, an app password — into a settings dialog. The new Outlook does none of that. When you add a Google account, it opens a Google sign-in in a browser window: you authenticate with Google directly, Google shows you a consent screen for “Microsoft apps and services,” and clicking Allow issues the token Outlook uses from then on.

That design is more secure, but it fails in specific, repeatable ways:

• The consent step never completed — the window was closed, or Cancel/Deny was clicked, so no token exists and Outlook asks again.
• A stale grant at Google — an older “Microsoft apps and services” permission from a previous attempt is broken, and every new sign-in reuses it instead of minting a fresh one. This is the classic authentication loop.
• A stale saved credential in Windows — Credential Manager can hold an old Google-related entry from Classic Outlook days that the sign-in keeps tripping over.
• IMAP switched off in Gmail — the account “adds” but nothing can sync, which looks like an add failure.

If you use Classic Outlook instead, the add process is completely different — see our step-by-step guide to adding Gmail to Outlook, which this article links back to in the Classic section below. And if your trouble is adding Yahoo rather than Gmail, the sibling guide is new Outlook can’t add Yahoo — same OAuth family, different token fix.

Fix 1: Complete the Google Sign-In and the Allow Step

Start clean and do the supported flow once, carefully:

See also Microsoft’s guide to adding a Gmail account to Outlook for Windows for the same new Outlook steps.

1. In the new Outlook, click the gear icon (Settings) > Accounts > Your accounts > Add account.
2. Enter your Gmail address and click Continue. A browser window (or an embedded sign-in page) opens with Google’s sign-in.
3. Sign in to Google with your normal Google password and complete any 2-Step Verification prompt.
4. On the consent screen — “Microsoft apps and services wants to access your Google Account” — scroll down and click Allow.
5. Wait for the browser to hand you back to Outlook and for the account to appear in the list. Do not close the browser window early; the handoff at the end is the step that creates the token.

If that completes, you are done. If Outlook loops back to the start or immediately asks again, the token Google issued is being rejected — almost always because of the old grant, which is Fix 2.

Fix 2: If New Outlook Can’t Add Gmail Account, Remove Stale Google Access and Re-Add It

When Google holds a broken earlier grant for “Microsoft apps and services,” new sign-ins keep colliding with it. Removing the grant forces Google to issue a completely fresh one.

1. In a browser, go to your Google Account (myaccount.google.com) and sign in.
2. Open Security, and find “Your connections to third-party apps & services” (on some accounts it is listed as Third-party apps with account access). Click See all connections.
3. Select Microsoft apps and services and choose Delete all connections / Remove all access. Confirm.
4. Back in the new Outlook, remove the half-added Gmail account if one is listed (Settings > Accounts > Your accounts > Manage > Remove).
5. Add the account again with Fix 1, clicking Allow when the consent screen appears — this time the grant is created fresh.

Fix 3: Clear Saved Google Credentials in Windows

PCs that have run Classic Outlook can hold saved Google-related credentials that interfere with the new app’s sign-in. Clearing them is safe: it removes saved entries, not accounts.

1. Click Start, type Credential Manager, and open it.
2. Click Windows Credentials.
3. Under Generic credentials, look for entries that mention Google or Gmail and expand each one, then click Remove. (Leave Microsoft/Office entries for accounts you actively use alone unless they name the same Gmail address.)
4. Restart the new Outlook and add the account again with Fix 1.

Fix 4: Turn On IMAP in Gmail

If the account now adds but mail never arrives — or the add ends with a sync error — check the switch on Gmail’s side:

1. In a browser, open Gmail, click the gear icon, then See all settings.
2. Open the Forwarding and POP/IMAP tab.
3. Under IMAP access, select Enable IMAP.
4. Click Save Changes at the bottom, then in Outlook remove and re-add the account (or wait and let it retry the first sync).

Using Classic Outlook Instead? The App Password Route

Everything above is the new Outlook’s flow. Classic Outlook for Windows still connects to Gmail the older way, and there the password-based route does exist — with Google’s modern guardrails:

1. Turn on 2-Step Verification in your Google Account (app passwords only exist when it is on).
2. In Google Account > Security, open App passwords and generate one for Mail. Google shows a 16-character code — that, not your real password, is what Classic Outlook uses.

3. Add the account in Classic Outlook with manual settings: imap.gmail.com, port 993, SSL/TLS for incoming; smtp.gmail.com, port 587, STARTTLS for outgoing — and the app password as the password.

The full Classic walkthrough, with screenshots of every dialog, is in our how to add Gmail to Outlook guide. Do not try to use an app password in the new Outlook — its Google sign-in is browser-based and has nowhere to accept one.

How to Stop the Gmail Sign-In Loop Coming Back

• Do not revoke “Microsoft apps and services” in your Google Account unless you are about to re-add the account — revoking it is what starts the re-authentication prompts.
• Expect one fresh sign-in after changing your Google password — complete it fully, including Allow, instead of dismissing it.
• One account, one grant: if you use the same Gmail in both Classic and new Outlook, that is fine — each app holds its own access. Removing access at Google affects both, so re-add in both afterwards.
• Keep 2-Step Verification on — the browser sign-in flow depends on your normal Google security settings.

When the account is added successfully, your Gmail appears in the new Outlook’s account list and the inbox starts filling:

Frequently Asked Questions

Outlook app is unable to add my Gmail account — why?

Because the browser sign-in handoff is failing, not because your password is wrong. The usual breaks: the consent screen’s Allow was never clicked (or the window was closed first), a stale “Microsoft apps and services” grant at Google is being reused, a dead Google credential is saved in Windows, or IMAP is off in Gmail. Fixes 1–4 in this guide clear them in that order.

Issue adding Gmail account to Outlook: stuck in an authentication loop — what fixes it?

Remove the existing grant at Google and let Outlook create a new one: Google Account > Security > third-party connections > Microsoft apps and services > Remove all access, then remove the account in Outlook and add it again, completing the sign-in and clicking Allow (Fix 2). The loop means the old token grant is broken; signing in again on top of it changes nothing.

I added a Gmail account in new Outlook. I need to do Gmail authentication every time I run a new Outlook. Is it just me?

It is not just you — it is the re-authentication version of the same problem. Outlook holds a token that Google keeps rejecting, so it asks for a fresh sign-in at every launch. Clear the stale grant at Google (Fix 2) and any Google entries in Credential Manager (Fix 3), then re-add the account once, completely. A healthy token is remembered between launches; repeated prompts are the symptom, not normal behavior.

Do I need an app password to add Gmail to the new Outlook?

No. The new Outlook signs you in through the browser and never asks for a Gmail password or an app password — there is no field for one. App passwords belong to the Classic Outlook route (with 2-Step Verification on and the manual IMAP/SMTP settings), covered in the Classic section above.

I clicked Allow but Outlook still says authentication failed. What now?

Do Fix 2 next — remove the “Microsoft apps and services” connection in your Google Account, remove the account from Outlook, and add it again so a fresh grant is issued. If it still fails after a fresh grant, clear the Google entries in Windows Credential Manager (Fix 3) and confirm IMAP is enabled in Gmail (Fix 4) before trying again.

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Still can’t add Gmail? Tell us exactly where it stops — the sign-in window, the Allow screen, or after the account appears — via our Contact page: servicedesk@howtofixerroronline.com, available 24 hours. For the Yahoo version of this problem, see new Outlook can’t add Yahoo account, and for Classic Outlook, our add Gmail to Outlook guide.