Accessing https://viewer.diagrams.net directly returns the same AADSTS50011 error.

[samswunk]

We are unable to authenticate to viewer.diagrams.net using Microsoft 365 ans only with this address. Authentication with sharepoint is ok, we can use app.diagrams.net with any trouble.

But, when generating a link with Publish > Link, instead of app.diagrams.net we have viewer.diagrams.net.

Authentication with viewer.diagrams.net consistently fails with the following Azure AD error:

AADSTS50011
The redirect URI https://viewer.diagrams.net/ms365 specified in the request does not match the redirect URIs configured for the application 417a451a-a343-4788-b6c1-901e63182565.

The issue affects multiple users and is reproducible regardless of the device or network used.

We already have verified the Azure AD application configuration associated with App ID 417a451a-a343-4788-b6c1-901e63182565 and :

• the Redirect URI https://viewer.diagrams.net is correctly registered;
• the Microsoft 365 authentication flow requests the correct Redirect URI;
• no recent deployment introduced this mismatch.
• Microsoft Entra ID is operating normally.
• MFA is functioning correctly.
• Conditional Access is not blocking authentication.
• Multiple users, devices and networks are affected.
• Accessing https://viewer.diagrams.net directly returns the same AADSTS50011 error.
  Environment:
• Microsoft 365 / Microsoft Entra ID
• Error code: AADSTS50011
• Azure Application ID: 417a451a-a343-4788-b6c1-901e63182565

Browser:
Chrome, FireFox and Edge
The link to generate the viewer.diagrams.net link is via Publish > Link

Is this issue occurring when using draw.io integrated within SharePoint/OneDrive, or through the standalone web app at app.diagrams.net with a file stored in OneDrive?

Both with draw.io integrated and through the standalone web app

Have you tried manually replacing 'viewer.diagrams.net' with 'app.diagrams.net' in the generated URL as a workaround — does that resolve the authentication issue?

When replacing 'viewer.diagrams.net' with 'app.diagrams.net' it is working fine

Is this a recent regression, i.e., did viewer.diagrams.net links with Microsoft 365 authentication work previously for you?

I did not try this before.

[draw-io-triage-bot]

👋 Thank you for opening this issue!

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Summary: Users are unable to authenticate via Microsoft 365 when accessing viewer.diagrams.net because the redirect URI https://viewer.diagrams.net/ms365 is not registered in the Azure AD application configuration (App ID 417a451a-a343-4788-b6c1-901e63182565), resulting in AADSTS50011 errors. Links generated by draw.io point to viewer.diagrams.net instead of app.diagrams.net, which works correctly.

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📝 Additional Information Needed

To help us investigate this more effectively, could you please provide:

• Browser: Which browser(s) are affected? This could be relevant if caching or redirect behavior differs.
• How the link is generated: Clarify the exact steps used to generate the viewer.diagrams.net link — is this via 'Publish' or 'Share' from within the draw.io app integrated with OneDrive/SharePoint?

We also have some questions:

• Is this issue occurring when using draw.io integrated within SharePoint/OneDrive, or through the standalone web app at app.diagrams.net with a file stored in OneDrive?
• Are you generating the viewer link via the 'Publish' or 'Share' functionality within draw.io? Could you describe the exact steps you follow to generate the link?
• Have you tried manually replacing 'viewer.diagrams.net' with 'app.diagrams.net' in the generated URL as a workaround — does that resolve the authentication issue?
• Is this a recent regression, i.e., did viewer.diagrams.net links with Microsoft 365 authentication work previously for you?

📋 Bug Report Template

**Environment:**
- draw.io version: [e.g., web app / desktop 24.x.x / Confluence plugin]
- Browser (if web): [e.g., Chrome 120, Firefox 121]
- OS: [e.g., Windows 11, macOS 14, Ubuntu 22.04]

**Steps to Reproduce:**
1. Go to ...
2. Click on ...
3. See error

**Expected Behavior:**
What you expected to happen.

**Actual Behavior:**
What actually happened.

**Screenshots/Files:**
If applicable, add screenshots or attach the .drawio file.

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_{🤖 This is an automated response to help with initial triage. A human maintainer will review this issue. If you've provided all the requested information, no further action is needed - we'll get back to you soon!}

[samswunk]

Thanks for reply !

Browser:

Chrome, FireFox and Edge

How the link is generated: Clarify the exact steps used to generate the viewer.diagrams.net link — is this via 'Publish' or 'Share' from within the draw.io app integrated with OneDrive/SharePoint?

Via Publish > Link

Is this issue occurring when using draw.io integrated within SharePoint/OneDrive, or through the standalone web app at app.diagrams.net with a file stored in OneDrive?

Both with draw.io integrated and through the standalone web app

Have you tried manually replacing 'viewer.diagrams.net' with 'app.diagrams.net' in the generated URL as a workaround — does that resolve the authentication issue?

When replacing 'viewer.diagrams.net' with 'app.diagrams.net' it is working fine

Is this a recent regression, i.e., did viewer.diagrams.net links with Microsoft 365 authentication work previously for you?

I did not try this before.