[BUG] Max 5x account cannot be authenticated in Claude Code subscription

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?

When logging in with Claude Code subscriptions by opening the link in Chrome (e.g., https://claude.com/cai/oauth/authorize?code=true&client_id=<mask>&response_type=code&redirect_uri=https%3A%2F%2Fplatform.claude.com%2Foauth%2Fcode%2Fcallback&scope=org%3Acreate_api
_key+user%3Aprofile+user%3Ainference+user%3Asessions%3Aclaude_code+user%3Amcp_servers+user%3Afile_upload&code_challenge=<mask>&code_challenge_method=S256&state=<mask>), the page raises "Claude Max or Pro is required to connect to Claude Code, Sign up for a Max or Pro subscription to connect your account, or use your API key.".

What Should Happen?

I have the Max 5x account. The browser has it already logged in the account. It should direct me to get code so I can paste it back into the terminal.

Error Messages/Logs

Claude Max or Pro is required to connect to Claude Code
Sign up for a Max or Pro subscription to connect your account, or use your API key.

Steps to Reproduce

1. Type claude in PowerShell
2. Pick " Claude account with subscription · Pro, Max, Team, or Enterprise"
3. Type c to copy the link and open it in a browser
4. The page raises "Claude Max or Pro is required to connect to Claude Code

Sign up for a Max or Pro subscription to connect your account, or use your API key."

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

v2.1.186

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Claude Code always raises "invalid API token" without regular patterns, in days or weeks. Previously, I had to log in again. However, this time, I cannot even authenticate anymore.

I am a researcher leveraging Claude Code to help my daily work and do not programmatically use it in any way. The interruption really affects my workflow, and I have to transfer to alternatives.