GitHub Copilot Not Working in IntelliJ IDEA — Chat Message Send Fails

What this error means

GitHub Copilot chat fails to send message in IntelliJ IDEA is a GitHub Copilot failure pattern reported for developers trying to fix github copilot chat not working in intellij idea after sending a message. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub Copilot plugin v1.9.0-251 on IntelliJ IDEA 2025.3.3 (Windows 11) fails when sending messages in Copilot chat. Users report the chat interface becomes unresponsive after the first message attempt. Affects paid Copilot subscription on JetBrains IDEs.

Common causes

• Developers using IntelliJ IDEA with GitHub Copilot plugin encounter chat failure where messages cannot be sent, blocking the AI pair programming workflow in the most popular JetBrains IDE.
• GitHub Copilot plugin v1.9.0-251 on IntelliJ IDEA 2025.3.3 (Windows 11) fails when sending messages in Copilot chat. Users report the chat interface becomes unresponsive after the first message attempt. Affects paid Copilot subscription on JetBrains IDEs.

Quick fixes

1. Confirm the exact error signature matches GitHub Copilot chat fails to send message in IntelliJ IDEA.
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/microsoft/copilot-intellij-feedback/issues/1673

Evidence note: GitHub Copilot plugin v1.9.0-251 on IntelliJ IDEA 2025.3.3 (Windows 11) fails when sending messages in Copilot chat. Users report the chat interface becomes unresponsive after the first message attempt. Affects paid Copilot subscription on JetBrains IDEs.

Related errors

• GitHub Copilot JetBrains plugin activation error
• GitHub Copilot chat connection timeout IntelliJ

FAQ

What should I check first?

Start with the exact GitHub Copilot chat fails to send message in IntelliJ IDEA 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 GitHub Copilot chat fails to send message in IntelliJ IDEA.