[BUG] Persistent authentication error "Beim Senden des Anmeldelinks ist ein Fehler aufgetreten" on Windows 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?

Authentication completely broken - unable to login to Claude via any method (Claude Code CLI in WSL Ubuntu AND web browser at claude.ai). Getting German error message despite English system locale.

Steps to Reproduce

1. Claude Code (WSL Ubuntu):

• Install Claude Code in WSL Ubuntu
• Run claude login
• Enter email address
• Get error: "Beim Senden des Anmeldelinks ist ein Fehler aufgetreten. Wenn das Problem weiterhin besteht, kontaktieren Sie den Support für Hilfe."

1. Web Browser:

• Go to claude.ai
• Attempt to login
• Same authentication failure occurs

Expected Behavior

Should receive login link via email and successfully authenticate on both platforms

Actual Behavior

Complete authentication failure across all Claude services - neither CLI nor web interface can send login links

Environment

• OS: WSL Ubuntu on Windows
• Claude Code installation: WSL Ubuntu environment
• Browser: Chrome and Edge
• System locale: English (but error appears in German)

Additional Context

• Critical: This affects ALL Claude services, not just Claude Code
• Error message in German suggests server-side issue
• Problem persists across different access methods
• Indicates broader Claude authentication infrastructure problem

Impact

Unable to access any Claude services whatsoever

What Should Happen?

Authentication completely broken - unable to login to Claude via any method (Claude Code CLI in WSL Ubuntu AND web browser at claude.ai). Getting German error message despite English system locale.

Steps to Reproduce

1. Claude Code (WSL Ubuntu):

• Install Claude Code in WSL Ubuntu
• Run claude login
• Enter email address
• Get error: "Beim Senden des Anmeldelinks ist ein Fehler aufgetreten. Wenn das Problem weiterhin besteht, kontaktieren Sie den Support für Hilfe."

1. Web Browser:

• Go to claude.ai
• Attempt to login
• Same authentication failure occurs

Expected Behavior

Should receive login link via email and successfully authenticate on both platforms

Actual Behavior

Complete authentication failure across all Claude services - neither CLI nor web interface can send login links

Environment

• OS: WSL Ubuntu on Windows
• Claude Code installation: WSL Ubuntu environment

Additional Context

• Critical: This affects ALL Claude services, not just Claude Code
• Error message in German suggests server-side issue
• Problem persists across different access methods
• Indicates broader Claude authentication infrastructure problem

Impact

Unable to access any Claude services whatsoever

Error Messages/Logs

Beim Senden des Anmeldelinks ist ein Fehler aufgetreten. Wenn das Problem weiterhin besteht, kontaktieren Sie den Support für Hilfe.

Steps to Reproduce

Steps to Reproduce

1. Claude Code (WSL Ubuntu):

• Install Claude Code in WSL Ubuntu
• Run claude login
• Enter email address
• Get error: "Beim Senden des Anmeldelinks ist ein Fehler aufgetreten. Wenn das Problem weiterhin besteht, kontaktieren Sie den Support für Hilfe."

1. Web Browser:

• Go to claude.ai
• Attempt to login
• Same authentication failure occurs

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.30 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_