[BUG] Bug Report — OAuth Login Failure in Claude for Excel & Claude for PowerPoint Add-ins

[OnFyreMarketing]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Subject: Bug Report—OAuth Login Failure in Claude for Excel & Claude for PowerPoint Add-ins

Hi Anthropic Support Team,

I'm unable to sign in to the Claude for Excel and Claude for PowerPoint add-ins. Both add-ins fail during the OAuth authorization flow with the following error:

“Autorisierung fehlgeschlagen
Redirect-URI https://pivot.claude.ai/auth/callback is not supported by client.”

Environment:

• OS: Windows (Microsoft 365)
• Apps affected: Claude for Excel AND Claude for PowerPoint (both from Microsoft Marketplace)
• Claude Plan: Pro
• Date of occurrence: March 22, 2026
• Region: Germany (EU)

Steps to reproduce:

1. Install Claude for Excel or Claude for PowerPoint from the Microsoft Marketplace
2. Open Excel or PowerPoint and activate the Claude add-in from the sidebar
3. Click “Sign in” and authenticate with Claude account credentials
4. Authorization fails immediately with the redirect URI error shown above

Expected behavior:
Successful OAuth authentication and access to the Claude add-in interface.

Actual behavior:
Login fails every time. The add-ins are completely unusable.

Additional context:

• The issue affects both add-ins identically, suggesting a shared backend OAuth configuration problem.
• The redirect URI (https://pivot.claude.ai/auth/callback) appears not to be registered as an allowed redirect URI on the OAuth server.
• Restarting Office and clearing the add-in cache did not resolve the issue.
• This issue is widely reported in the Microsoft Marketplace reviews for both add-ins (average rating ~2.5/5 stars), with numerous 1-star reviews citing the same login failure.
• Related GitHub issues: [BUG] Claude for Excel & PowerPoint: "Extra inputs are not permitted" on code_execution_20250825.use_web_search_purpose #25747, [BUG] Claude PowerPoint add-in: "Tool names must be unique" error on first message #27193 (filed in Anthropic/claude-code as there is no dedicated repo for the Office add-ins).

This appears to be a server-side OAuth misconfiguration that requires a fix from Anthropic. Given that the login is the very first step of the user experience, I'd appreciate it if this could be prioritized.

Thank you for looking into this.

Best regards,
Janis Krziwanie
OnFyre Marketing – onfyre.de

What Should Happen?

After clicking "Sign in" in the Claude for Excel or Claude for PowerPoint add-in and authenticating with my Claude account, the OAuth flow should complete successfully and I should see the main add-in interface, ready to use.

Error Messages/Logs

Autorisierung fehlgeschlagen
Redirect-URI https://pivot.claude.ai/auth/callback is not supported by client.

This error appears identically in both the Excel and PowerPoint add-ins immediately after attempting to sign in.

Steps to Reproduce

1. Install "Claude by Anthropic" for Excel from the Microsoft Marketplace
2. Open Microsoft Excel (Microsoft 365, Windows)
3. Activate the Claude add-in from the sidebar (Home > Add-ins)
4. Click "Sign in" and enter Claude account credentials
5. OAuth authorization fails with the redirect URI error above
6. Repeat steps 1–5 with "Claude by Anthropic" for PowerPoint — same result

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

Unknown. The issue appears to be ongoing since at least early 2026 based on user reviews.

Claude Code Version

N/A — This is not a Claude Code issue. It affects the Claude for Excel and Claude for PowerPoint Office Add-ins hosted at pivot.claude.ai.

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

• The redirect URI (https://pivot.claude.ai/auth/callback) is not registered as a valid redirect URI on the OAuth server. This is a server-side configuration issue.
• Region: Germany (EU)
• Claude Plan: Pro
• Both add-ins have ~2.5/5 star ratings in the Microsoft Marketplace. The majority of 1-star reviews report this exact login failure.
• Clearing the Office Add-in cache (%LOCALAPPDATA%\Microsoft\Office\16.0\Wef) did not resolve the issue.
• Restarting Office did not resolve the issue.
• Related issues: [BUG] Claude for Excel & PowerPoint: "Extra inputs are not permitted" on code_execution_20250825.use_web_search_purpose #25747 (API validation error, fixed server-side), [BUG] Claude PowerPoint add-in: "Tool names must be unique" error on first message #27193 (“Tool names must be unique” error)
• Unlike those issues, this OAuth redirect URI problem has not been addressed yet.

Screenshot.bmp

[tonypstephens]

I have a cleint who is getting the same issues. Has there been any update on this?

I'm not sure if it's just a typo in the error message but ti seems to be missing a "/" - https:/pivot.cluade.ai

[MaikJaek]

This issue has started to affect users in our organization as well. A fix for this would be highly appreciated.

[malankriel]

Same issue for me when trying to install the add-in:

[Jberchtikou]

Confirming this issue — same error on Claude for PowerPoint add-in.

Plan: Claude Pro
Office version: [ta version, ex. Microsoft 365, build 16.x]
OS: [Windows 10/11 ou macOS]
Error: Authorization failed — Redirect URI https://pivot.claude.ai/auth/callback is not supported by client
Cache clearing (%LOCALAPPDATA%\Microsoft\Office\16.0\Wef) did not resolve.

[yash050297]

Getting same issue for both Excel and PowerPoint Add-ins. All users in my organization are having same issue.
Plan: Claude AI - Teams plan
OS: Windows
Since it's a login issue which is the first touchpoint for a user, appreciate if this can be prioritized.

[rangarajanramya-maker]

Same issue - just paid for a $20/ month subscription
"Authorization failed
Redirect URI https:/pivot.claude.ai/auth/callback is not supported by client."

[BartoszBilejczyk]

Getting same issue for both Excel and PowerPoint Add-ins. All users in my organization on Windows are having same issue.
Plan: Team
OS: Windows

Thanks!

[pspowell]

I have the same problem with Office 365 on fully patched Win11

[eumeme]

same on Excel plugin

[Pascalvanderbroek]

Same on the Excel Plugin!

[saving-sherman]

also getting it on PowerPoint Plugin

[RyneNZ]

I have a cleint who is getting the same issues. Has there been any update on this?

I'm not sure if it's just a typo in the error message but ti seems to be missing a "/" - https:/pivot.cluade.ai

The fix is simple manually add the / to the url and login works. Would be nice for addon to be updated to the correct url