[BUG] Cowork returns 403 "Request not allowed" on Pro plan — Chat and Code work fine, VPN global mode confirmed

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?

Cowork feature consistently fails with a 403 authentication error every time a task is submitted. Regular Chat and Code modes work perfectly on the same account and same machine.

I am located in mainland China using Clash VPN in Global (TUN) mode — all traffic including subprocesses is routed through VPN. api.anthropic.com is confirmed reachable. The error persists regardless of proxy configuration, which suggests this is a server-side rejection, not a network issue.

What Should Happen?

Cowork should authenticate successfully and process tasks, just like Chat and Code modes do on the same account.

Error Messages/Logs

Failed to authenticate. API Error: 403 {"error":{"type":"forbidden","message":"Request not allowed"}}

Steps to Reproduce

1. Log in to Claude Desktop with a Pro account
2. Enable Clash VPN in Global mode (all traffic routed)
3. Confirm Chat and Code modes work correctly
4. Open the Cowork tab
5. Submit any task
6. Immediately receive 403 "Request not allowed" error

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Account: milkyway.yin@gmail.com
Plan: Claude Pro
OS: macOS
Claude Desktop version: Claude 1.1617.0 (8d6345) 2026-04-09T16:10:15.000Z

Troubleshooting already attempted:

• Verified Pro subscription is active at claude.ai/settings
• Chat and Code modes confirmed working on same account
• Clash set to Global (TUN) mode — covers all subprocesses including Cowork VM
• Set proxy via launchctl setenv for Desktop app process
• Cleared all app cache (Local Storage, Session Storage, Cookies, Cache) from ~/Library/Application Support/Claude/
• Re-authenticated via fresh OAuth login
• Reinstalled Claude Desktop

The 403 persists across all attempts, confirming this is a server-side issue.

Related issues: #28486, #32816, #34268, #38066