Auth Error when chatting with agent

[a_a8 (a a)]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Cursor says “Authentication Error” when I chat with it in agent window. I am logged in already.

Steps to Reproduce

Install Cursor
Login
Say hi in agent chat window

Screenshots / Screen Recordings

Operating System

MacOS

Version Information

Version: 3.17.8
VS Code Extension API: 1.128.0
Commit: 2fdd31c9f33f7fbe501f2d57772dc5bf64b63620
Date: 2026-08-20T02:18:12.724Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 40.10.3
Chromium: 144.0.7559.236
Node.js: 24.15.0
V8: 14.4.258.32-electron.0
xterm.js: 6.1.0-beta.291
OS: Darwin arm64 25.4.0

For AI issues: add Request ID with privacy disabled

Request ID: f5062b2d-906d-45c3-82f1-cba8d4d43ee8
{“error”:“ERROR_NOT_LOGGED_IN”,“details”:{“title”:“Authentication error”,“detail”:“If you are logged in, try logging out and back in.”,“isRetryable”:false,“additionalInfo”:{},“buttons”:,“planChoices”:,“analyticsMetadata”:{“actionRequired”:“login”}},“isExpected”:true}
Authentication error If you are logged in, try logging out and back in.
ActionRequiredError: Authentication error If you are logged in, try logging out and back in.
at Dhf (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7993:121989)
at Czs (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7993:120905)
at Xhf (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7994:13617)
at Object.classify (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7994:18165)
at Ghf (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7994:5896)
at async Bzs.run (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:7994:17517)
at async dce.runAgentLoop (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:8126:34492)
at async Txo.streamFromAgentBackend (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:15063:15118)
at async Txo.getAgentStreamResponse (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:15063:33370)
at async wIe._submitChatMaybeAbortCurrent (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:8104:3052)

Does this stop you from using Cursor

Yes - Cursor is unusable

[deanrie]

Hey, thanks for the report and the Request ID. It helps us see what’s going on.

Your account looks fine, and logging in on the website works. The issue is that the Cursor app on your Mac is holding onto an old session that the server rejects, and a new login doesn’t overwrite it. That’s why you see “Authentication error” even though you’re technically signed in.

To reset it:

• Open Cursor Settings using the gear icon or Cmd+Shift+J, then click Sign Out from there.
• Fully quit Cursor with Cmd+Q, don’t just close the window.
• Open Cursor again and sign in, let the browser flow finish, and make sure it sends you back to the app.

If it still happens after that, tell me if the browser login completes and whether it returns you to Cursor, and we’ll dig deeper.