Authentication error

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I launched Cursor in existing project, and for any sentence in agent chat received this messages “Authentication error.If you are logged in, try logging out and back in.” I repeated several times - Log out / Log in , reintsll ide, clear cach - nothing! I’ve Pro plan.

Steps to Reproduce

Any messages in agent chat raise this error “Authentication error. Log out / Log in back”

Operating System

Windows 10/11

Version Information

Version: 3.7.36 (system setup)
VS Code Extension API: 1.105.1
Commit: 776d1f9d76df50a4e0aeca61819a88e7c1b861e0
Date: 2026-06-13T00:31:56.287Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
xterm.js: 6.1.0-beta.256
OS: Windows_NT x64 10.0.19045

For AI issues: which model did you use?

any model

Does this stop you from using Cursor

Yes - Cursor is unusable

Hey, thanks for the report. On Windows this is almost always something you can fix locally, and the first thing to check is your system clock. Even being off by a couple of hours can break token validation and cause exactly this error even if you’re signed in.

Try these steps in order:

  1. Sync your Windows clock: Settings > Time & language > Date & time > Sync now. This fixed the same issue for other users.
  2. Remove any custom Base URL if you set one: Cursor Settings > Models > disable the overridden Base URL.
  3. Fully quit Cursor, not just close the window, then open it again. After that, sign out in Cursor Settings and sign back in.
  4. Run Cursor Settings > Network > Run Diagnostics. This helps rule out a proxy, VPN, or antivirus that’s stripping the Authorization header.

Start with step 1, it’s the most common cause. Let me know how it goes. If it still doesn’t help, send the Request ID Chat menu in the top right > Copy Request ID and we can dig deeper.