API Error 500: Internal Server Error when sending any message in Claude Code (Cursor, Windows)

Hi, I’m experiencing a consistent issue with Claude Code inside Cursor IDE.
Whenever I type ANY message in the Claude terminal (even a simple “hola”), the system immediately throws an API Error 500.

API Error: 500 {"type": "error", "error": {"type": "api_error", "message": "Internal server error"}, "request_id": "req_011CV1tljyzxr9UeHspIjZF"}

Steps to Reproduce:

Open Cursor IDE

Open Claude Code (Sonnet 4.5 – Claude Max)

Type anything in the prompt (e.g., “hola”)

Immediately receive API Error: 500

Expected Behavior:

Claude Code should process and respond normally to the prompt.

Environment:

Editor: Cursor IDE

Claude Code Version: v2.0.50

Model: Sonnet 4.5 (Claude Max)

Operating System: Windows

Internet Connection: Stable

Reproducible: Always (100% of the time)

Request ID: req_011CV1tljyzxr9UeHspIjZF

<img width="1723" height="627" alt="Image" src="https://github.com/user-attachments/assets/d001bece-9635-43d3-8ac5-54a2eecd040e" />