[BUG] Bug Report: 401 Invalid Bearer Token Immediately After Successful Login

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?

Claude Code returns a 401 authentication error immediately after a successful login. The login flow completes and shows "Login successful", but any subsequent message returns a 401 Invalid bearer token error. The UI also always displays "API Usage Billing" even after logging in with a subscription account (Option 1). A colleague using the exact same organization account on a different machine has no issues — their Claude Code works correctly and shows "Claude Max" after login.

What Should Happen?

After completing the OAuth login flow (Option 1 · Claude account with subscription), Claude Code should authenticate correctly, display "Claude Max" as the plan, and respond to messages without any 401 error.

Error Messages/Logs

Please run /login · API Error: 401 {"type":"error","error":{"type":"authentication_error","message":"Invalid bearer token"}

Credentials file after login correctly shows:

{
  "claudeAiOauth": {
    "subscriptionType": "max",
    "rateLimitTier": "default_claude_max_20x"
  }
}

Steps to Reproduce

1. Run claude logout
2. Delete %USERPROFILE%\.claude\.credentials
3. Run claude and type /login
4. Select Option 1 (Claude account with subscription · Pro, Max, Team, or Enterprise)
5. Complete OAuth flow in Chrome browser — shows "Login successful"
6. Type any message (e.g., hello or test)
7. Immediately receives 401 Invalid bearer token error
8. Repeating /login and sending a message always results in the same 401 error

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

-

Claude Code Version

2.1.110 (native installer)

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

• Account type: Organization account (Max plan, rateLimitTier: default_claude_max_20x)
• No ANTHROPIC_API_KEY environment variable is set
• Reinstalling via native installer (claude install) did not resolve the issue
• Deleting credentials and logging in multiple times did not resolve the issue
• A colleague using the exact same organization account on a different Windows machine works fine and shows "Claude Max" after login
• Browser used for OAuth: Google Chrome (single profile, organization account active)
• The issue appears to be that the OAuth token is accepted during login but immediately rejected when making API calls