Claude in Chrome extension OAuth still fails with "Authorization failed" — recurrence of #69051/#34176, both now closed/locked

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet as a new, still-open report — the prior reports are closed/locked (see below)
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude in Chrome extension OAuth authorization consistently fails with "Authorization failed — This isn't working right now" immediately after reaching claude.ai/oauth/authorize. This is a recurrence of a previously reported and independently-reproduced issue — both prior threads are now closed and locked, so this is a fresh report to keep it visible, not a duplicate filed carelessly.

Prior reports (closed/locked, no fix landed):

• #69051 — closed as duplicate of #34176, auto-locked. I posted an independent two-machine reproduction there on 2026-09-20 with no maintainer response since.
• #34176 — the original report this was merged into, also closed.

The bug is back / never actually resolved: same symptom, same client_id, same failure point.

Steps to Reproduce

1. Install/reinstall the Claude in Chrome extension.
2. In Claude Code, enable the Claude in Chrome connector / click the extension icon to authorize.
3. Browser opens claude.ai/oauth/authorize?client_id=dae2cad8-15c5-43d2-9046-fcaecc135fa4&response_type=code&scope=user%3Aprofile+user%3Ainference+user%3Achat&redirect_uri=chrome-extension%3A%2F%2F...%2Foauth_callback.html&...
4. Page fully renders (real Anthropic UI, footer shows "Logged in as [account]", "Switch account" — so the request reaches the backend and recognizes the user), but immediately shows "Authorization failed — This isn't working right now." The "Try again" button does not help.

Evidence / what's been ruled out

Independently reproduced on two separate machines/networks with identical results:

• Full extension reinstall from scratch
• Completely clean new Chrome profile, no other extensions/cookies/history
• claude.ai cookies cleared
• Chrome sync disabled for "Extensions" data type
• No conflicting multiple Google accounts in the profile
• System clock checked against the HTTP Date header — 0 drift
• Tested both on direct connection and through a VPN tunnel (different exit IP) — identical failure
• System-level VPN disabled entirely — no change
• Not a Cloudflare challenge — real rendered UI, no JS challenge page
• Second machine, different physical computer, different network/IP: base claude.ai login works fine, but the extension pairing/authorization step fails with the same error on the same screen

This points at a server-side issue with the OAuth authorization flow for the Claude Code ↔ browser extension pairing (redirect_uri chrome-extension://... handling), not a client-side/environment issue.

Expected Behavior

Clicking through the OAuth flow should complete successfully, redirect to oauth_callback.html, store the access token, and connect the extension to Claude Code.

Environment

• OS: macOS (Darwin 27.2.0)
• Browser: Chrome (latest)
• client_id: dae2cad8-15c5-43d2-9046-fcaecc135fa4
• Reproduced on 2 independent Macs, different networks

Is this a regression?

Yes — this previously worked, and was reported broken as far back as #34176.