GitHub Copilot ProxiedResponseError After npx Upgrade — Fix Guide

What this error means

ProxiedResponseError [FetchResponseError]: HTTP 200 response does not appear to originate from GitHub is a GitHub Copilot failure pattern reported for developers trying to resolve github copilot proxiedresponseerror that appears after upgrading npx via homebrew. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue (2026-05-08) with exact error signature triggered by npx upgrade. Clear causal relationship between package manager update and Copilot failure. Exact error string is highly searchable.

Common causes

• After a routine npx upgrade via Homebrew (to v11.12.1), copilot.vim throws a ProxiedResponseError on initialization, breaking the Copilot language server. Developers search for the exact error string to find a quick fix.
• GitHub issue (2026-05-08) with exact error signature triggered by npx upgrade. Clear causal relationship between package manager update and Copilot failure. Exact error string is highly searchable.

Quick fixes

1. Confirm the exact error signature matches ProxiedResponseError [FetchResponseError]: HTTP 200 response does not appear to originate from GitHub.
2. Check the GitHub Copilot account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/github/copilot.vim/issues/282

Evidence note: GitHub issue (2026-05-08) with exact error signature triggered by npx upgrade. Clear causal relationship between package manager update and Copilot failure. Exact error string is highly searchable.

Related errors

• Copilot language server not starting
• npx copilot-language-server version mismatch

FAQ

What should I check first?

Start with the exact ProxiedResponseError [FetchResponseError]: HTTP 200 response does not appear to originate from GitHub text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed GitHub Copilot workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without ProxiedResponseError [FetchResponseError]: HTTP 200 response does not appear to originate from GitHub.