OpenRouter API: Connection Fails Only with Claude Models

Discussion
1

I’ve encountered a specific issue when using OpenRouter API in Cursor:
Connection failed. If the problem persists, please check your internet connection or VPN
image

Connections consistently fail ONLY when trying to use Claude models (claude-3.7, etc.). Other OpenRouter models work perfectly fine, and Claude via OpenRouter works normally in other applications. And it has been more than two days.

Details:

  • Only Claude models through OpenRouter fail in Cursor
  • Other OpenRouter models (like GPT-4, etc.) work normally in Cursor
  • Claude through OpenRouter works fine in other applications
  • Issue persists even after extending timeout settings
  • Verified my OpenRouter API key is correct (works with other models)
  • Confirmed my network connection is stable (other models and applications work fine)
  • When verifying the API using Claude, it works perfectly and shows up in OpenRouter usage logs
  • But when trying to use Claude in actual chat:
    • Connection fails
    • No usage logs appear in OpenRouter
    • No error response from OpenRouter

Environment:

  • Cursor Version: 0.48.7
  • Operating System: Windows 11 (x64)
  • Request ID: 82884686-58c4-4fc3-85ef-6bd63cd72941
1 Like
2

Have you confirmed the model name is exactly as OpenRouter is expecting?

We sometimes use an alias for models when running them in Cursor directly, but OpenRouter will need the exact name to know which model you want.

If that all seems fine, can you send over a Request ID?

3

I think model name is correct. I am not using default model name in Cursor but adding new model name manually according to openrouter documentation

Request ID: 5a51eec3-4148-4ccc-8c78-7494e388ae1c

4

Hello, I have the same problem, can you help me solve it?
Cursor Version：0.48.7
Operating System：Windows 11
Request ID：ae041928-c1a4-4f96-9416-9ec9d5256d27

5

@Ajay-Seed Looked like some SSL issue here, are you using a self-signed certificate or something here?

@TSxingke That ID isn’t showing in our backend, which suggests Cursor isn’t able to connect to our servers, can you try to disable HTTP/2 and try again?

6

Same issue here!

“Connection failed. If the problem persists, please check your internet connection or VPN
(Request ID: c1fc9095-2b90-4dce-837b-429d3cc1b59d)”

1 Like
7

I should clarify that I am using a proxy (V2rayN), but I’ve tested extensively and found that:

  1. Direct Anthropic API works in Cursor (with or without proxy)
  2. Other OpenRouter models work fine (with or without proxy)
  3. Only Anthropic through OpenRouter fails in both cases

Since the issue persists regardless of proxy usage, and I’ve tested the SSL connections all SSL certificates are properly signed, not self-signed certificate. Could there be another reason for this specific Anthropic-OpenRouter connection issue?

8

Hi everyone, I’m here to report the same issue. I have many other models with OpenRouter and all of them are working fine.
Any “anthropic/...” fails, it just keeps loading forever.
Request ID: c40bc042-f416-41e8-9a5a-371683f9093b

To make sure it’s not about the naming, I used a wrong OpenRouter model name like “claude-3.7-sonnet” and I instantly got the error message.

Request failed with status code 400: {"error":{"message":"claude-3-7-sonnet-20250219 is not a valid model ID","code":400},"user_id":”user_*******"}

Details:

  • Only Claude models through OpenRouter fail in Cursor
  • Other OpenRouter models (like GPT-4, etc.) work normally in Cursor
  • Claude through OpenRouter works fine in other applications
  • Issue persists even after extending timeout settings
  • Verified my OpenRouter API key is correct (works with other models)
  • Confirmed my network connection is stable (other models and applications work fine)
  • When verifying the API using Claude, it works perfectly and shows up in OpenRouter usage logs
  • But when trying to use Claude in actual chat:
    • Connection fails
    • No usage logs appear in OpenRouter
    • No error response from OpenRouter

Environment:

  • Cursor Version: 0.49.5
  • Operating System: Darwin arm64 24.0.0 (macOS 15.0.1)