Microsoft Oauth New Outlook issue

Question

Microsoft update earlier this month disabled Oauth authentication for New Outlook and it will no longer connect with the internet. Is there an update available to fix?

Answer 1

There is no confirmed fix yet for iCloud authentication in New Outlook. The issue started late March and is tied to ongoing service updates for iCloud account support. Updates are being rolled out gradually with no exact release date. Keep Outlook updated and retry the account setup, since the fix is applied on the service side, not as a single patch.

Answer 2

Yes, a fix is already released through Windows Update, not New Outlook. Go to Settings, Windows Update, select Check for updates, install all available updates, then restart your PC. This resolves the sign in issue without needing to remove and re add your account.

Answer 3

Hello, are you signing in with a work account or a personal Outlook.com account?

Open Settings, go to Accounts, then Email and accounts, remove the affected account under Accounts used by other apps, then restart your PC. After restart, open New Outlook, add the account again, and complete the sign in prompt. This refreshes the Windows Web Account Manager token used for OAuth and resolves sign in failures when the app cannot connect.

Answer 4

OAuth (Modern Authentication) has not been disabled in New Outlook; instead, Microsoft is deprecating Basic Authentication for Outlook.com and requiring Modern Authentication (OAuth) across supported apps.

If New Outlook is no longer connecting, the issue is unlikely to be a global disabling of OAuth and more likely related to the specific profile or local state. From the provided guidance, the supported remediation for New Outlook connection issues is to reset its local state and then sign in again:

1. Close New Outlook.
2. Run the reset command for New Outlook (olk.exe --clearLocalState).
3. Start New Outlook again and re‑enter the account credentials when prompted, confirming the connection details.

This reset has been reported to restore functionality when New Outlook stops working or fails to connect.

If the problem is that an older Outlook or a non‑Microsoft app was using Basic Authentication, there is no “fix” to re‑enable Basic Authentication. Instead, the supported path is to:

• Use a version of Outlook that supports Modern Authentication (all current Microsoft 365 subscription SKUs and Outlook 2021 LTSC with build 11601.10000 or higher), and
• Ensure the account is added using Outlook.com/Exchange (not POP/IMAP), because POP/IMAP connections to Outlook.com do not support Modern Authentication and will stop working as Basic Authentication is fully removed.

There is no context indicating a separate update that re‑enables OAuth; the documented direction is to move to Modern Authentication‑capable Outlook clients and configurations and, for New Outlook connection failures, to clear local state and reconfigure the account.

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References:

• New Outlook has stopped working, Fails when starting after 30 to 60 seconds - Microsoft Q&A
• Modern Authentication Methods now needed to continue syncing Outlook Email in non-Microsoft email apps
• Outlook and other apps are unable to connect to Outlook.com when using Basic authentication