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Codex Issues / #39405

ChatGPT for Excel account sign-in fails in Office WebView2 with Cloudflare Error 1010 on Windows

Open 💬 0 comments Opened Aug 19, 2026 by its4u88-spec

What version of the Codex App are you using?

Current stable Windows Codex app. The failure occurs in the ChatGPT for Excel add-in before Codex can connect to the workbook.

What subscription do you have?

ChatGPT paid subscription.

What platform is your computer?

Windows x64.

  • Microsoft Excel: Office LTSC 2021 x64, build 16.0.14334.20756
  • Office product: ProPlus2021Volume
  • Microsoft Edge WebView2 Runtime: 150.0.4078.65

What issue are you seeing?

Summary

The ChatGPT for Excel add-in loads, but Continue with ChatGPT account cannot complete authentication on Windows desktop Excel. The Office embedded authentication dialog opens a bps.openai.com URL and Excel then reports:

ADD-IN ERROR
This add-in could not be loaded.

This blocks the ChatGPT-account login required for the Codex/ChatGPT Excel integration. API-key mode works, but it uses separate API billing and is not an equivalent workaround.

Reproduction

  1. Open desktop Excel on Windows.
  2. Open the official ChatGPT for Excel add-in.
  3. Select Continue with ChatGPT account.
  4. The Office embedded authentication dialog opens.
  5. The dialog fails and Excel shows the add-in load error.

Diagnostic evidence

The problem is isolated to the Office embedded WebView authentication request.

  • DNS and HTTPS connectivity to bps.openai.com work.
  • WinHTTP is using a direct connection, with no proxy.
  • Windows was fully restarted after signing out of Office and closing all Office applications.
  • The Office add-in WebView2 cache was cleared and regenerated.
  • Only Microsoft Windows Defender is in use.
  • There is no third-party antivirus, endpoint security, VPN, proxy, web protection, or SSL/TLS inspection tool installed or enabled.
  • The failure remains reproducible after all of the above.
  • The exact one-time bps.openai.com/.../auth/start URL was recovered from the Office WebView2 history for controlled comparison. The URL itself is intentionally omitted because it contains one-time authentication parameters.
  • Requesting that URL with an Office/WebView-like client signature returns HTTP 403 with Cloudflare Error code: 1010.
  • Requesting the same URL, from the same machine and network, with a normal Edge/Chrome browser signature returns HTTP 200.
  • A captured failing response included a Cloudflare Ray ID ending in -ICN.
  • Opening the one-time URL in a normal external browser cannot complete the flow because the page expects the Office host callback (window.external).

This comparison indicates that the account, subscription, DNS, network route, and URL are valid, while the Office embedded WebView request is rejected before authentication completes.

OpenAI Support reviewed the diagnostics, stated that the issue does not appear to be related to the local environment, and confirmed that it remains under active engineering review. Support case identifiers are available privately if maintainers need to correlate the report.

What steps can reproduce the bug?

  1. Use Windows desktop Excel with the official ChatGPT for Excel add-in.
  2. Click Continue with ChatGPT account.
  3. Observe the embedded bps.openai.com authentication dialog fail with an Excel add-in load error.
  4. Compare the one-time authentication request from Office WebView2 and a normal Chromium browser:
  • Office/WebView-like request: HTTP 403, Cloudflare 1010.
  • Normal Edge/Chrome request: HTTP 200.

What is the expected behavior?

The Office WebView2 authentication request should be accepted, allow ChatGPT account sign-in to complete, and return control to the Excel add-in so Codex/ChatGPT can connect to the workbook.

Alternatively, the add-in should provide a supported external-browser authentication flow that securely returns the completed session to Excel.

Additional information

  • Changing the Windows default browser does not change the browser control used by Office add-ins.
  • Attempting to override the WebView2 user agent for the Excel process did not affect the Office authentication dialog.
  • Copying browser cookies or tokens into the Office WebView was not attempted and would not be a supported workaround.
  • This appears distinct from Codex Browser plugin initialization issue #39136. That issue fails at the Codex trusted-path check; this report fails in the ChatGPT for Excel Office WebView authentication request at Cloudflare.

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