[BUG] OAuth error: Request failed with status code 400

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?

hi,
hopefully someone has an idea how to fix the following. thanks in advance!

i am using vs code.
installed the official extension "Claude Code for VS Code".

trying to log in using Anthropic Console account to use pay as you go api usage billing.
i open the link in the browser and click authorize.
but then immediately get the error
_OAuth error: Request failed with status code 400_

Same behaviour if i copy and open the authorization link in the browser manually.
i am getting the code which i should input in claude code in vs code to complete authorization.
i do that but i also get the same error message after i submit that.

Behaviour is the same no matter if i use the ui or terminal.

Please help!

---

Claude Code
Version 2.1.123:

VS Code
Version: 1.118.0 (user setup)
Commit: 9b8ae15a8cf95b9bce1b590b42954530f440e816
Date: 2026-04-28T15:54:22-07:00
Electron: 39.8.8
ElectronBuildId: 13870025
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26200

What Should Happen?

Authorization should finish successfully 😅

Error Messages/Logs

OAuth error: Request failed with status code 400

Steps to Reproduce

Try to login

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.123

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

Same behaviour in windows powershell (with and without admin rights)