[BUG] Paid Max acct routed to /onboarding after authentication

Preflight Checklist

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

What's Wrong?

[MMagic-link and Google login both route existing Max subscriber to /onboarding "Let's create your account" — 4 days locked out, mobile app session still authenticated

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NOTE ON REPO CHOICE: This is not a Claude Code bug. I am a Claude Code user, but the CLI fields are N/A (I checked the "latest version" preflight box only because the template requires it to submit). Filing here per the precedent in #47290, #51002, #57164, #60022, #68861, and #75638, where backend auth and billing failures required engineering escalation because Fin AI Support could not resolve them and no other public channel reaches engineers.

What's Wrong?

I am an active, currently billed Claude Max subscriber. As of 4 days ago, every browser and desktop login attempt routes to claude.ai/onboarding displaying "Let's create your account" with my email shown as verified at the bottom of the page. No dashboard, no error message, no path back to my existing account.

This is the same backend identity-mapping failure documented in #36797, #39788, #51002, #57164, #58566, #60022, #68861, and #75638. Mine is the magic-link variant, closest to #60022.

What Should Happen?

A verified email that maps to an existing, actively billed account should authenticate into that account. The auth callback should never silently fall through to the new-user onboarding flow. At minimum this state should surface an explicit error and route to support rather than offering a "Create account" button that can spawn a duplicate.

Steps to Reproduce

1. an existing, active, paid Claude Max account (individual plan).
2. Go to claude.ai in any browser and enter the account email.
3. Open the magic link received at that address, in the same browser that requested it.
4. Observe: redirect to claude.ai/onboarding, "Let's create your account," email shown as verified.
5. "Continue with Google" with the same identity produces the same result.

Ruled Out

• Reproduces in Chrome Incognito (no cookies, no extensions)
• Reproduces on a second desktop browser
• Reproduces on mobile browser over cellular, sharing no cache/cookies/network with desktop
• Site data cleared for claude.ai, claude.com, anthropic.com: reproduces
• No VPN or proxy in use
• Individual plan, so SSO and provisioned org seats are not applicable
• Magic link opened in the requesting browser, not an in-app webview

Evidence the account exists and is billed

My Claude mobile app session remains authenticated and fully functional, showing the Max badge on the account. Billing is current. Receipt numbers, card last four, and account details available privately through official support channels.

Not Done, Deliberately

I have not clicked "Create account." Per #51002, doing so creates a duplicate account under the same email with a different auth provider and locks the user out of the original paid account.

Support Path So Far

Fin AI Support conversation ID: 215475349207069 Human escalation requested. Adding this here so Anthropic can match this report to my account without me posting my email address publicly.

Claude Code Version

N/A

Platform

claude.ai web, Claude Desktop, Claude Android app

Is this a regression?

Yes — login worked previously on all surfaces.

What Should Happen?

A verified email that maps to an existing, actively billed account should authenticate into that account. The auth callback should never silently fall through to the new-user onboarding flow. At minimum this state should surface an explicit error and route to support rather than offering a "Create account" button that can spawn a duplicate.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. an existing, active, paid Claude Max account (individual plan).
2. Go to claude.ai in any browser and enter the account email.
3. Open the magic link received at that address, in the same browser that requested it.
4. Observe: redirect to claude.ai/onboarding, "Let's create your account," email shown as verified.
5. "Continue with Google" with the same identity produces the same result.

Claude Model

_No response_

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Na

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_