Connection Error occurs depending on prompt content (Windows 11)

Support Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I’m experiencing persistent “Connection Error” issues on Cursor (Windows 11).

I tested extensively across multiple AI models, including:

  • Opus 4.5
  • Sonnet 4.5
  • GPT-5.1 Codex Max / Mini
  • GPT-5.2
  • Gemini 3 Flash
  • Grok Code

Results:

  • Some prompts work successfully on all models.
  • However, certain prompts or executions fail consistently with “Connection Error” on every model.
  • When a prompt fails, it fails regardless of the model selected.

Network diagnostics pass, and Cursor support confirmed that requests reach the AI provider but sometimes no response is returned, depending on the content or execution path.

If anyone has experienced similar content-dependent connection errors or found a workaround, I would really appreciate any information.

Steps to Reproduce

Steps to Reproduce:

  1. Launch Cursor on Windows 11.
  2. Open any project (new or existing).
  3. Open Chat (CMD+L) or run an AI feature such as Agent, Composer, or Auto.
  4. Enter a prompt that requires multi-step reasoning or longer processing.
  5. Execute the prompt.

Expected Behavior

Expected Result:
The AI should return a normal response without showing a connection error.

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.2.44 (system setup)
VSCode Version: 1.105.1
Commit: 20adc1003928b0f1b99305dbaf845656ff81f5d0
Date: 2025-12-24T21:41:47.598Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26200

Additional Information

Additional Notes:

  • Some simple prompts succeed.
  • Certain prompts consistently fail with “Connection Error”.
  • When a prompt fails, it fails across all AI models tested (GPT, Claude, Gemini, Grok, etc.).
  • Network diagnostics pass, and Cursor support confirmed the request reaches the provider but no response is returned.

Does this stop you from using Cursor

No - Cursor works, but with this issue

1 Like
Unable to Reach Model Provider Opus4.5, Sonnet4.5 and Gemini 3 Pro
2

Hey, thanks for the report.

This looks like a known issue affecting certain regions since Dec 29. The symptoms are identical: simple prompts work, but certain content or long requests fail across all models.

To help narrow it down, we need a bit more info:

  1. Region: What region/country are you in?

  2. Console errors: Go to Help > Toggle Developer Tools > Console, reproduce the issue, and send a screenshot of the red errors.

  3. New Request ID: After the error, copy the Request ID (Chat menu > Copy Request ID).

  4. Network: Are you using a VPN or proxy?

In the meantime, please try:

  1. Change DNS:

    • Settings > Network > Change adapter options > connection properties > IPv4
    • Try Cloudflare DNS: 1.1.1.1 and 1.0.0.1
    • Or Quad9: 149.112.112.112 and 9.9.9.9
    • Restart Cursor

  2. Disable HTTP/2:

    • File > Preferences > Cursor Preferences > search for “HTTP” > “HTTP Compatibility Mode” > select HTTP/1.1
    • Restart Cursor

Similar cases:

Send the requested info and I’ll pass it to the team with priority right away.

3

Thanks for the follow-up.

Here is a Request ID from a previously reproduced occurrence of the issue:

  • Request ID: 204fefd1-1ca9-4613-a559-29e89fd64c24
  • Additional ID shown: 3221226505

This was generated when a longer / more complex prompt failed with a “Connection Error”.
The behavior matches what I am currently experiencing.

If you need a newly generated Request ID from a fresh reproduction, please let me know and I will capture one.

1 Like