"Unauthorized User API key" when using Claude Sonet 4

[Quy_Pham]

Describe the Bug

I’m Paid user with Pro plan. Today I’ve tried a lot but still receive an “Unauthorized User API key” error when try to use any model from anthropic (claude sonet 4, 3.7, …).
And I retry to call directly with anthropic with a same API key in Postman, and it works. So I don’t think a root cause is my API key.

Steps to Reproduce

I’m Paid user with Pro plan. Today I’ve tried a lot but still receive an “Unauthorized User API key” error when try to use any model from anthropic (claude sonet 4, 3.7, …).
And I retry to call directly with anthropic with a same API key in Postman, and it works. So I don’t think a root cause is my API key.

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.2.4
VSCode Version: 1.99.3
Commit: a8e95743c5268be73767c46944a71f4465d05c90
Date: 2025-07-10T16:53:59.659Z (1 wk ago)
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

[Quy_Pham]

Oh, just found out it works again when I’ve turned off “Override OpenAI Base URL” in Cursor Setting > Model

[condor (Condor (Tee))]

hi @Quy_Pham and welcome to Cursor Forum.

Wow great that you found the cause for this issue! Thank you for that and the detailed report.

Feel free to mark your own answer as a solution. Solutions help others know what works in which cases