Microsoft 365 Error Codes

How to Fix Office 365 401 Unauthorized Link Error

Camila Milosovich Oct 13, 2026 870 views

Question details

The user needs to resolve a 401 Unauthorized error encountered when attempting to open an Office 365 link or install the software.

How to Troubleshoot a 401 Error When Accessing an Office 365 Link

Product: Microsoft Office 365
Device & OS: Windows
Scenario: Accessing a shared Office 365 link or initiating the Office installation process.
Observed behavior: A 401 Unauthorized error appears, blocking the user from viewing the linked content or completing the Office setup.

Before you start

Make sure you know the exact Microsoft or work account credentials associated with your Office 365 subscription before making system changes.

Solution 1Recommended

Clear Windows Credentials and Re-authenticate

Use this solution to remove outdated or conflicting login details that might be causing the authentication failure.

A 401 error usually happens when Windows caches old or incorrect account credentials. Clearing the Credential Manager forces Office to request a fresh authentication token.

Sign out and close Office

Sign out of your account in any open Office applications, then close all Microsoft Office programs completely.

Open Credential Manager

Click the Windows Start menu, type 'Control Panel', and open it. Navigate to 'User Accounts' and click on 'Credential Manager'.

Remove outdated credentials

Select 'Windows Credentials'. Look for any saved credentials related to Microsoft Office or Office 365, click on them to expand the details, and select 'Remove'.

Sign in again

Open your web browser, visit Office.com, and sign in with the correct authorized Microsoft account to successfully access your link.

Clear Windows Credentials and Re-authenticate

Uninstalling Office: If the issue persists and involves an Office installation error, you may need to completely uninstall Office using the Microsoft removal tool before reinstalling.

Solution 2

Verify Account Permissions and Subscriptions

Ensure you are using the correct account authorized to access the specific link or resource.

Free Microsoft Office alternative

Avoid Authentication Errors with WPS Office

If persistent Microsoft 365 account errors and subscription issues are slowing you down, try WPS Office. It is a powerful, lightweight, and free alternative that lets you work on your documents seamlessly without complex login requirements.

Fully compatible with Microsoft Office formats like DOCX, XLSX, and PPTX.No persistent online authentication required to access and edit local files, avoiding 401 errors.Lightweight design ensures quick installation without complicated account setups.Familiar user interface allows for immediate productivity with zero learning curve.

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Frequently Asked Questions

What exactly does a 401 Unauthorized error mean in Office 365?

A 401 error indicates that the server could not verify your identity. This typically happens if you are not signed in, your session has expired, or you are signed in with an account that does not have permission to access the link.

Do I have to reinstall Office to fix a 401 error?

Not always. Often, simply clearing your old login data from the Windows Credential Manager and signing back in will resolve the issue. Reinstallation is mostly required if the Office desktop application's core license files are corrupted.

Why do I get a 401 error when accessing a shared company document?

This happens when you try to open the link using a personal Microsoft account instead of your designated work account. Switch to your organization's authorized account, or ask the sender to adjust the sharing permissions to allow your current account.

Microsoft Office Error Codes