Unable to reach model provider error when local mcp is enabled

Support Bug Reports
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1

Hi,

When I enable my local stdio MCP server in cursor, only chats in Auto model selection mode works. Any request with a specific model selected fails with the following error:

Request ID: 397b289a-e0a3-43c5-8fb1-73753f1852e2
{“error”:“ERROR_OPENAI”,“details”:{“title”:“Unable to reach the model provider”,“detail”:“We’re having trouble connecting to the model provider. This might be temporary - please try again in a moment.”,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:false}

If I disable my MCP server, everything works as expected. I could not find much info in MCP logs. Any suggestions on why this might be happening and how to debug it? Thanks

3

Hey, thanks for the report. This looks like a known pattern. There’s a similar case with Perplexity MCP: Can only use Composer 1 with Perplexity MCP server

In that case, only one mode worked (Composer 1), and specific models crashed with ERROR_OPENAI. It’s most likely related to how different chat modes initialize MCP servers.

To find the cause, could you try:

  1. Test in a clean profile:
cursor --user-data-dir="CursorData/Test"

Open the project, enable the MCP server, and try a specific model (for example, Claude or GPT). Does it work?

  1. If it works, check extensions:
  • Help > Toggle Developer Tools > Console, send a request using a specific model and look for errors
  • Disable extensions one by one
  1. Share here:
  • Which exact models you tested (Claude, GPT, Gemini?)
  • Your Cursor version (Menu > About Cursor > Copy)
  • If you have them, errors from the Developer Console

The clean profile test result is especially important. It’ll show whether the issue is with your config or extensions, or with the MCP server itself.

4

Thanks for the response.

  1. It did not work with a clean profile either.
  2. I tried with all the extensions disabled as well.
  3. Tested all models other than Composer-1. None of them work.

Version details:

Version: 2.3.41
VSCode Version: 1.105.1
Commit: 2ca326e0d1ce10956aea33d54c0e2d8c13c58a30
Date: 2026-01-16T19:14:00.150Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 25.2.0

Console logs attached.

vscode-app-1769150072437.txt (20.1 KB)

5

Looks like it’s a DNS issue. Your computer can’t resolve api2.cursor.sh at all. This isn’t a Cursor bug, it’s a network block.

Try this:

  1. Run Network Diagnostics:

    • Cursor Settings > Network > Run Diagnostics
    • Paste the results here

  2. Check DNS manually in Terminal:

    nslookup api2.cursor.sh
ping api2.cursor.sh

  3. Are you using a VPN or a corporate network? Try:

    • Turning off the VPN
    • Testing on another network (mobile hotspot)
    • If it’s a corporate network, the firewall might be blocking *.cursor.sh domains

  4. Check DNS settings on macOS:

    • System Settings > Network > your network > Details > DNS
    • Try adding public DNS (8.8.8.8, 1.1.1.1)

If api2.cursor.sh still won’t resolve even with public DNS on a mobile hotspot, then it’s likely an ISP-side or regional block. Otherwise, it’s local network configuration.

Let me know the Network Diagnostics and nslookup results, and we’ll see exactly where it’s getting blocked.

6

@deanrie - After updating to latest version 2.4.21, the issue is no longer reproducible in my setup.

For clarity, yes I am behind a corporate VPN. However, the issue was reproducible even when I was in my home network with VPN turned off. It puzzles me how the setup worked when my local MCP was disabled.