InternalError popped up, can't use Cursor

Support Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

An unexpected error occurred on our servers. Please try again, or contact support if the issue persists.
Copy Request (94256020-5975-4bda-bd28-75a52b4e51a3)
After updating to version 3.9.16, an internal error popped up. I sent a question but got no response from the Cursor agent; it just kept waiting for hours. Changing the model made no difference.

Steps to Reproduce

Just sending simple words to Cursor..

Expected Behavior

The agent will process my words and deal with it

Operating System

Windows 10/11

Version Information

Version: 3.9.16 (user setup)
VS Code Extension API: 1.105.1
Commit: 042b3c1a4c53f2c3808067f519fbfc67b72cad80
Date: 2026-06-27T06:41:01.941Z
Layout: editor
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.256
OS: Windows_NT x64 10.0.26100

For AI issues: which model did you use?

All models

Additional Information

I got few errors or unavailable connection by running the network diagnostics.

Does this stop you from using Cursor

Yes - Cursor is unusable

5

I also face this problem. It just shows those error lines.
This morning, after cursor updated, I tried to add custom model, but it would not work. When I add my custom model, It shows nothing in model list. Now all the models are not working.
Request ID: 24e781b3-a6b6-41b8-999c-330b55a88a2d
[unknown] Network disconnected
RetriableError: [unknown] Network disconnected
at uAS (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12056:27795)
at EMc (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12056:26530)
at Fny (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12057:11929)
at Object.classify (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12057:16434)
at hAS (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12057:5824)
at async Oqm.runWithSharedTurnRunner (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12057:15786)
at async iH.runAgentLoop (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:24486:3041)
at async Lkh.streamFromAgentBackend (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:24505:13862)
at async Lkh.getAgentStreamResponse (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:24505:22888)
at async IRe.submitChatMaybeAbortCurrent (vscode-file://vscode-app/d:/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:12142:2399)

6

I face the same problem with 3.9.16 and 3.8.24.

I Downgraded to 3.7.42 so i can use the IDE.

7

Yes，I also fixed it by downgrading to 3.7.42. Thank you!

9

Hi @Yingshi_Wang

Thanks for flagging this, and sorry for the disruption. This isn’t a server outage on your account. The pattern here (Agent and Chat hanging or failing right after an update, while sign in and the Marketplace still work) almost always points to a proxy, VPN, or network filter sitting between Cursor and our servers.

A bit of background on why it tends to show up after an update: Cursor has always preferred HTTP/2 for AI requests (Agent, Chat, API, and the connection health “Ping”), and HTTP/2 can’t be routed through a proxy. Recent builds moved these AI requests into a separate process and added connection health checks, so a proxy or VPN setup that used to limp along quietly can now fail outright with messages like “Network disconnected” or “ConnectError: [unavailable]”. Sign in, Marketplace, and downloads use a different path that does respect the proxy, which is why those keep working. The same thing can make the model list come up empty, since the model lookup takes the same route.

Here’s how to get working again:

  1. Open Settings, search for HTTP/2, and turn on Disable HTTP/2. (Or add "cursor.general.disableHttp2": true to your settings.json.)

  2. If you use a proxy, also set:

    {
  "cursor.general.disableHttp2": true,
  "http.proxy": "http://<your-proxy-host>:<port>",
  "http.proxySupport": "override"
}

  3. Fully quit Cursor and reopen it.

If you’re still stuck after trying the steps above, please go to Cursor Settings > Network > Run Diagnostics and let us know which specific checks fail. If you can, also send a fresh Request ID with Privacy Mode turned off, and we’ll dig in further.