Many models stopped working

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Opus 4.5
Sonnet 4.5
Gemini 3 pro
And other models stopped working.

Woking:
GPT 5.1
Composer 1

Steps to Reproduce

Just select :
Opus 4.5
Sonnet 4.5
Gemini 3 pro

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.1.39
Commit: 60d42bed27e5775c43ec0428d8c653c49e58e260
Date: 2025-11-27T02:30:49.286Z
Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Cursor/2.1.39 Chrome/138.0.7204.251 Electron/37.7.0 Safari/537.36

Does this stop you from using Cursor

Yes - Cursor is unusable

2

Hey, thanks for the report. Several models (Sonnet 4.5, Gemini 3 Pro) have been experiencing provider connectivity issues over the past week, and the team is actively investigating this.

Please try the following steps:

  • Network diagnostics: Cursor Settings → Network → Run Diagnostics (share results)
  • HTTP/2 fix: CMD+, → search “HTTP/2” → enable “Disable HTTP/2” → restart Cursor → test in a new Agent chat
  • New chat: Create a new Agent chat (don’t switch models mid-conversation)
  • Request IDs: If errors persist, share Request IDs from failed attempts (chat menu top right → Copy Request ID)

Could you also confirm:

  • Are you using a VPN, corporate network, or proxy?
  • What specific error messages appear when models fail?

Let me know if the HTTP/2 change helps.

3

Agent
[2025-11-28T10:09:50.501Z] Starting stream
[2025-11-28T10:09:50.501Z] Pushing first message
[2025-11-28T10:09:53.179Z] Response: ‘foo’ in 2678ms
[2025-11-28T10:09:53.679Z] Pushing next message
[2025-11-28T10:09:54.008Z] Response: ‘foo’ in 829ms
[2025-11-28T10:09:54.509Z] Pushing next message
[2025-11-28T10:09:54.783Z] Response: ‘foo’ in 775ms
[2025-11-28T10:09:55.284Z] Pushing next message
[2025-11-28T10:09:55.550Z] Response: ‘foo’ in 766ms
[2025-11-28T10:09:56.052Z] Pushing next message
[2025-11-28T10:09:56.405Z] Response: ‘foo’ in 855ms
[2025-11-28T10:09:56.405Z] Result: Error: Bidirectional streaming is not supported by the http2 proxy in your network environment

4

Chat
[2025-11-28T10:09:50.500Z] Starting stream
[2025-11-28T10:09:53.253Z] Response: ‘foo’ in 2752ms
[2025-11-28T10:09:54.324Z] Response: ‘foo’ in 1071ms
[2025-11-28T10:09:55.213Z] Response: ‘foo’ in 889ms
[2025-11-28T10:09:56.197Z] Response: ‘foo’ in 984ms
[2025-11-28T10:09:57.214Z] Response: ‘foo’ in 1017ms
[2025-11-28T10:09:58.197Z] Result: Error: Streaming responses are being buffered by a proxy in your network environment

5

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6

Unfortunately, your advice didn’t help.

7

Thanks for the screenshot. I see errors in Diagnostics: “Chat responses are being buffered by a proxy” and “Bidirectional streaming is not supported by the http2 proxy” - this confirms the issue with the proxy/network that’s buffering streaming.

Since Disable HTTP/2 is already enabled, try:

  • Disabling VPN/proxy completely and testing on a home network
  • Cursor Settings → Network → disable “Use Proxy” if it’s enabled
  • Restarting the router or using a mobile hotspot for testing

Could you please share:

  • The Request ID from the last failed chat (chat menu → Copy Request ID)
  • Are you using a VPN, corporate network, or proxy?

I’ll pass this to the team with your details.