Troubleshooting GitHub Copilot Not Working in IntelliJ IDEA

GitHub Copilot integrates with JetBrains IDEs, including IntelliJ IDEA, to provide AI-powered code suggestions. When this integration fails, various factors can be the cause, preventing the plugin from offering suggestions or connecting to the service. Addressing these issues typically involves checking plugin status, account authentication, network connectivity, and IDE configuration.

Common Reasons for GitHub Copilot Failure

Several issues can prevent GitHub Copilot from functioning correctly within the IntelliJ IDEA environment. Understanding these common causes helps in diagnosing the specific problem.

• Plugin Issues: The GitHub Copilot plugin might be disabled, outdated, or corrupted.
• Account and Licensing: A valid GitHub account is required, and it must have an active GitHub Copilot subscription. The IDE must be correctly logged into this account.
• Network Connectivity: The IDE needs to communicate with GitHub's servers to fetch suggestions. Firewalls, proxies, VPNs, or general internet connection problems can block this communication.
• IDE Compatibility and State: The Copilot plugin might not be compatible with the specific version of IntelliJ IDEA being used. Internal IDE issues like corrupted caches or indexing problems can also interfere.
• Configuration Conflicts: Other installed plugins or specific IDE settings might conflict with Copilot's operation.

Checking Plugin Status and Installation

The first step in troubleshooting is to verify the state of the GitHub Copilot plugin within IntelliJ IDEA.

• Navigate to File > Settings (or IntelliJ IDEA > Preferences on macOS).
• Select Plugins from the left-hand menu.
• In the Installed tab, search for "GitHub Copilot".
• Ensure the plugin is installed and the checkbox next to it is ticked, indicating it is enabled.
• Check for available updates. If an update is available, install it and restart the IDE.
• If the plugin is installed but not working, consider uninstalling and then reinstalling it from the Marketplace tab within the Plugins settings. A restart of the IDE is required after installation or uninstallation.

Verifying GitHub Account and Subscription

GitHub Copilot requires an active subscription linked to a GitHub account, and the IDE must authenticate with this account.

• Confirm that the GitHub account associated with the IDE login has a valid and active GitHub Copilot subscription. This can be checked on the GitHub website under the account's Copilot settings.
• In IntelliJ IDEA, check the GitHub login status. This is typically found under File > Settings (or Preferences) > Version Control > GitHub.
• Ensure the correct account is logged in. If unsure, log out and log back in. The login process involves authorizing the IDE via a web browser, confirming the link between the IDE and the GitHub account.
• Verify the user performing the login in the IDE matches the user with the active Copilot subscription.

Addressing Network and Firewall Issues

Network restrictions are a common cause of connection failures for services like GitHub Copilot.

• Confirm basic internet connectivity from the machine running IntelliJ IDEA.
• Check if a firewall (operating system or corporate) is blocking outgoing connections that Copilot needs. Copilot typically communicates over standard HTTPS (port 443).
• If using a proxy server, ensure that IntelliJ IDEA is configured correctly to use the proxy settings. Proxy configuration is usually found under File > Settings (or Preferences) > Appearance & Behavior > System Settings > HTTP Proxy.
• VPNs can sometimes interfere with network routing. Try temporarily disabling the VPN to see if Copilot functionality is restored. If so, consult the VPN or network administrator to ensure Copilot's required endpoints are not blocked.
• Specific endpoints might need to be accessible. While GitHub doesn't provide an exhaustive list of Copilot endpoints for firewall configuration, ensuring access to github.com and associated services necessary for plugin communication is generally sufficient.

Investigating IDE Specific Problems

IntelliJ IDEA's internal state and configuration can sometimes lead to issues with plugins.

• IDE Compatibility: Ensure the installed version of the GitHub Copilot plugin is compatible with the specific version and build of IntelliJ IDEA being used. Compatibility information is usually listed on the plugin's page in the JetBrains Marketplace website.
• Cache Invalidation: Corrupted caches can cause unexpected behavior. Try invalidating caches and restarting the IDE via File > Invalidate Caches / Restart.... Select "Invalidate and Restart".
• Indexing Issues: Copilot relies on the IDE's understanding of the codebase, which comes from indexing. Ensure project indexing has completed successfully. Status indicators for indexing are typically found in the bottom-right corner of the IDE window.
• Plugin Conflicts: Although less common, another installed plugin could potentially conflict with GitHub Copilot. As a diagnostic step, try temporarily disabling other non-essential plugins to see if the issue resolves.
• IDE Logs: IntelliJ IDEA generates logs that can contain error messages related to plugin failures. Accessing logs via Help > Show Log in Explorer (or Finder on macOS) can provide clues about the underlying problem. Look for errors or warnings related to "Copilot" or "GitHub".

Other Potential Solutions

If the above steps do not resolve the issue, consider these additional measures.

• Check GitHub Status Page: Occasionally, issues might stem from the GitHub Copilot service itself. Check the official GitHub status page for any reported outages or performance issues.
• IDE Updates: Ensure IntelliJ IDEA itself is updated to the latest stable version. Sometimes, underlying IDE improvements or bug fixes resolve plugin compatibility problems.
• Reinstall IntelliJ IDEA: As a last resort, if local configuration or installation issues are suspected, a clean reinstallation of IntelliJ IDEA can resolve deep-seated problems. Ensure project settings and personal configurations are backed up if needed.
• Seek Support: If problems persist after trying these steps, consulting the GitHub Copilot documentation, the JetBrains support resources for IntelliJ IDEA, or the GitHub community forums for Copilot can provide further assistance. Providing relevant details like IDE version, Copilot plugin version, operating system, and any error messages from the IDE logs is helpful when seeking support.