[Bug] Connection Error even with verified personal Anthropic API Key ($5 balance)

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

“Connection Error” and “Usage Limit” popups persist despite using a paid personal Anthropic API key on a Free Plan account.

Steps to Reproduce

  1. Log in to Cursor with a Free Plan account.

  2. Enable “Anthropic API Key” in settings and verify it ($5 balance confirmed).

  3. Try to send a message. Result: “You’ve hit your usage limit” popup appears immediately.

  4. Log out and try again. Result: “Connection Error” appears with a Request ID.

  5. Disabled Windows Firewall and V3 Antivirus, but the issue persists.

Expected Behavior

Cursor should use my personal Anthropic API key to process requests, regardless of my Free Plan status.

Screenshots / Screen Recordings

스크린샷 2026-04-13 182033.png
스크린샷 2026-04-13 182033.png1618×990 48.7 KB

Operating System

Windows 10/11

Version Information

Version: 3.0.16 (user setup)
VSCode Version: 1.105.1
Commit: 475871d112608994deb2e3065dfb7c6b0baa0c50
Date: 2026-04-09T05:33:51.767Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26100

For AI issues: which model did you use?

Sonnet 4.6 (Medium)

For AI issues: add Request ID with privacy disabled

503b77a0-3ca0-4f6d-8c72-9abdc5962256

Additional Information

I have already checked my Anthropic API balance ($5.00 remaining) and verified the key in Cursor settings. I even disabled my firewall and AhnLab V3 antivirus, but the connection error persists only in Cursor. This seems to be a conflict between the Free Plan status and personal API key usage.

Does this stop you from using Cursor

Yes - Cursor is unusable

5

Hey, this isn’t a bug, it’s expected behavior. Using your own API keys (BYOK) in Agent and Ask modes now requires a Pro subscription. On the Free plan, keys won’t work, even if they’re valid and have balance.

It used to work as an undocumented option, but the policy has changed. Details here: Ask mode with my own API Key required Pro Subscription

Options:

  • Upgrade to Pro ($20/month), then your Anthropic key will work
  • Stay on Free and use the built-in free models, without your own keys

Let me know if you have any questions.