New Outlook Can’t Add Yahoo Account: Fix the OAuth Error

Adding Yahoo Mail to the new Outlook is supposed to be a two-minute job: pick Yahoo, sign in in the browser, done. Instead, for a lot of people the sign-in window dies on a stark error page — “This site can’t be reached”, ERR_FAILED, on an address that begins with oauthRedirect. Or the account adds, works for a while, and then quietly stops syncing. If the new outlook can’t add yahoo account, the fixes below take the problem in order, starting with the supported add.

That failed page is the clue. Yahoo sign-in in the new Outlook runs through a browser OAuth handoff, and the oauthRedirect error means the handoff got stuck in the app’s local token cache — the sign-in tokens stored in the Olk and OneAuth folders on your PC. Clearing that cache is the fix this error actually needs, and it is Fix 2 below. Start with the supported add (Fix 1) so you know the account itself is fine.

Quick Answer: Add Yahoo the supported way — Settings > Accounts > Your accounts > Add account > Yahoo — and finish the Yahoo sign-in in the browser window (Fix 1). If the sign-in dies with oauthRedirect / ERR_FAILED, close Outlook and rename the %localappdata%\Microsoft\Olk and OneAuth folders, then re-add — that forces a clean OAuth token (Fix 2). Then check that ports 993/465/587 are not blocked (Fix 3). Manual IMAP settings are a labeled fallback only (Fix 4), and Yahoo business (Turbify) accounts have their own sign-in-first workaround at the end.

How Yahoo Sign-In Works in the New Outlook (OAuth)

Like Gmail, Yahoo in the new Outlook is not added with your Yahoo password typed into Outlook. You choose Yahoo on the Add account screen, a browser window opens, you sign in to Yahoo there, and Yahoo issues Outlook a sign-in token via OAuth. The token is cached locally — in the app’s Olk data folder and in the OneAuth folder that Windows apps share for account tokens.

Two practical consequences:

• There is no app-password field in the new app. Yahoo app passwords exist, but they belong to the manual/Classic route — our add Yahoo and AOL Mail to Outlook guide covers that flow for Classic Outlook.
• When the cached token breaks, re-trying the sign-in changes nothing — the app keeps presenting the same dead token. That is why “was working, now not” and the oauthRedirect failure both point at the cache, not at your Yahoo account.

New Outlook Can’t Add Yahoo Account? Fix 1: Add Yahoo the Supported Way

Do the clean add once, end to end:

1. In the new Outlook, click the gear icon (Settings) > Accounts > Your accounts > Add account.
2. Choose Yahoo from the provider list (or enter your Yahoo address and let Outlook offer the Yahoo sign-in).
3. When the browser window opens, sign in to Yahoo with your normal Yahoo password and complete any verification prompt.
4. Let the browser hand you back to Outlook — do not close the window mid-handoff — and wait for the account to appear in the list and start syncing.

If that finishes, you are done. If the browser page fails with the oauthRedirect error instead of completing, go straight to Fix 2. Microsoft’s official guide to adding a Yahoo account in Outlook covers the same supported add if you want to cross-check the steps.

Fix 2: oauthRedirect / ERR_FAILED — Clear the Token Cache

This is the signature fix for this error: rename the two folders that hold the broken token state so the apps rebuild them.

1. Close the new Outlook completely (right-click its taskbar icon > Close window; if it lingers, end it in Task Manager).
2. Press Windows key + R, type %localappdata%\Microsoft and press Enter.
3. In the Microsoft folder, find Olk and rename it to Olk.old.
4. Go back to the address bar, type %localappdata%\Microsoft\OneAuth — open the parent first the same way if needed — and rename the OneAuth folder to OneAuth.old.
5. Reopen the new Outlook and add your Yahoo account again with Fix 1. A fresh token is issued, and the redirect completes.

Renaming rather than deleting keeps a way back, and nothing in either folder is your mail — messages live on Yahoo’s servers and sync down again.

Fix 3: Check That the Mail Ports Are Not Blocked

A blocked port looks a lot like a broken sign-in: the OAuth flow completes but the account cannot reach Yahoo’s servers, and the failure surfaces as a timeout during or just after the add. Yahoo’s servers use port 993 (incoming IMAP) and 465 or 587 (outgoing SMTP).

1. Open Windows Security > Firewall & network protection > Allow an app through firewall and confirm Outlook is allowed on your network type.
2. If you run a third-party antivirus with its own firewall or web shield, check that it is not blocking the Outlook app or those ports — temporarily pause only the firewall/web-shield feature to test, then turn it straight back on.
3. On a work or school network, these ports are sometimes blocked by policy; testing once on your home connection settles whether the network is the cause.

Fix 4: Manual IMAP Settings (Fallback Only)

If the OAuth add still will not complete, Yahoo can be added with manual server settings — treat this as a fallback, because the OAuth route is the one Yahoo and the new Outlook are built around:

• Incoming (IMAP): imap.mail.yahoo.com — port 993 — SSL/TLS
• Outgoing (SMTP): smtp.mail.yahoo.com — port 465 with SSL/TLS (or 587)
• Password: if your Yahoo account has two-step verification turned on, your normal password will be rejected here — generate an app password in Yahoo (Account > Account security > Generate app password), name it for Outlook, and use that 16-character code as the password.

For Classic Outlook, the app-password route is the normal one — our Yahoo and AOL in Outlook guide covers it step by step.

Yahoo Business (Turbify) Accounts: Sign In to Webmail First

Yahoo business mail accounts (the Turbify-hosted ones) hit this failure more than personal accounts, and the threads on it point to a sign-in cookie problem: the OAuth window cannot complete because Yahoo has no live sign-in session to hand off from. The workaround:

1. Open your default browser and sign in to Yahoo Mail webmail with the business account. Leave that tab open and signed in.
2. Now add the account in the new Outlook (Fix 1). The browser handoff can reuse the live session and completes instead of erroring.
3. If it still fails, clear the token cache (Fix 2) and repeat — webmail sign-in first, then the add.

How to Stop Yahoo Sign-In Problems Coming Back

• When Yahoo stops syncing after working fine, do not change settings at random — the token has usually expired or been revoked; remove the account and re-add it, clearing the token cache (Fix 2) if the add fails.
• After changing your Yahoo password, expect to re-add the account once; complete the browser sign-in fully.
• Keep the OAuth route as your default. Manual settings and app passwords are a fallback — mixing the two is how accounts end up half-configured.
• Leave the Olk and OneAuth folders alone between fixes; manual meddling there is a cause of this error, not a cure — rename them only as Fix 2 describes.

When the account connects properly, your Yahoo inbox appears in the new Outlook and starts to sync:

Frequently Asked Questions

How do I get my Yahoo email account to sync with Outlook for Windows (new)? It was working, now it’s not.

“Was working, now not” is the token-expiry pattern: the cached OAuth token Yahoo issued has expired or been revoked, and the app cannot renew it silently. Remove the account in Settings > Accounts > Your accounts, then add it again and complete the Yahoo browser sign-in. If the add itself fails, clear the token cache first (rename the Olk and OneAuth folders, Fix 2) so a completely fresh token is issued.

What is the oauthRedirect “This site can’t be reached / ERR_FAILED” error?

It is the browser handoff page failing during Yahoo’s OAuth sign-in: Yahoo redirects the sign-in back to Outlook through a special local address, and when the app’s token state is corrupt the redirect dead-ends on that error page. The fix is to clear the token cache — rename %localappdata%\Microsoft\Olk and the OneAuth folder with Outlook closed — then re-add the account (Fix 2).

Do I need a Yahoo app password for the new Outlook?

Not for the supported route. The new Outlook adds Yahoo through the browser OAuth sign-in, so your normal Yahoo sign-in is used and no app password is involved. An app password is needed only if you add the account with manual IMAP settings (Fix 4) while two-step verification is on — and in Classic Outlook, where the app-password route is the standard one.

Why did my Yahoo account stop syncing in the new Outlook?

Usually the token, not the settings: Yahoo revoked or expired the sign-in token (a password change, a security check, or simply age), and the app cannot refresh it. Remove and re-add the account. If the re-add fails with oauthRedirect/ERR_FAILED, clear the Olk and OneAuth token folders first. A Gmail account failing the same way has a parallel fix — see new Outlook can’t add Gmail.

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Still can’t add Yahoo? Tell us the exact failure — the oauthRedirect page, a sign-in that never finishes, or an account that adds but won’t sync — via our Contact page: servicedesk@howtofixerroronline.com, available 24 hours. Classic Outlook users should use the Yahoo/AOL setup guide instead, and the Gmail sibling of this guide is here.