GitHub Copilot suggestion failures fall into four categories: authentication problems (token expired or revoked), network/proxy issues (Copilot's servers unreachable), extension-level configuration (Copilot disabled for this file type or workspace), and editor conflicts (another extension interfering). The fastest diagnosis is checking the Copilot status icon in your editor's status bar — it tells you which category you're in before you waste time troubleshooting the wrong thing.
No grey inline suggestion text appears as you type
Copilot status icon in VS Code status bar shows a warning or disconnected indicator
Chat panel shows 'GitHub Copilot could not connect to server' or 'Authentication failed'
Suggestions worked yesterday but stopped today with no apparent change
Copilot works in some files but not others (e.g., works in .js but not .py)
Pressing Alt+\ (trigger suggestion) does nothing
Error in VS Code output panel: 'GitHub Copilot: not enabled for this repository'
GitHub Copilot has a per-language enable/disable setting. If someone (you or a workspace config) disabled Copilot for Python, TypeScript, or another language, you'll see no suggestions in those files. This is the most common cause of 'works in some files but not others' reports.
Copilot authenticates through your GitHub account. If you changed your GitHub password, revoked the VS Code token, enabled 2FA without re-authenticating, or the token expired, Copilot silently stops working. The status bar icon changes to a warning, but it's easy to miss.
GitHub Copilot connects to api.githubcopilot.com and other GitHub endpoints. Corporate proxies, firewalls, VPNs, DNS filtering, and aggressive security software all commonly block these connections. If Copilot works on personal WiFi but not corporate network, this is the cause.
Other AI coding extensions (Tabnine, Codeium, Amazon CodeWhisperer, Cursor's Copilot mode) can conflict with GitHub Copilot. Some intercept the suggestion API, others register the same keyboard shortcuts. Having multiple inline-suggestion extensions enabled simultaneously causes erratic behavior.
GitHub Copilot requires an active Individual, Business, or Enterprise subscription. If your payment failed, your organization removed your seat, or your trial ended, Copilot will silently stop suggesting. Check github.com/settings/copilot for your subscription status.
The GitHub Copilot VS Code extension occasionally ships bugs that break suggestions, then is quickly patched. If you're on an outdated extension version after a known bug release, updating usually resolves it immediately.
GitHub allows repository owners and organizations to disable Copilot on specific repositories — particularly for public repos or repos with sensitive code. If Copilot works everywhere except one project, check the repo's settings or ask your org admin about Copilot policies.
When to try: First — diagnose before fixing
In VS Code, look at the status bar (bottom left). The GitHub Copilot icon shows its state: check mark = active, spinning = loading, warning triangle = error. Click the icon for a quick status summary. For detailed diagnostics: open Output panel (View → Output) and select 'GitHub Copilot' from the dropdown. Error messages here tell you exactly what's wrong — look for 'Authentication' or 'Could not connect' messages.
When to try: If Copilot works in some file types but not others
Open VS Code Settings (Cmd+, on Mac, Ctrl+, on Windows). Search for 'copilot enable'. You'll see a list of languages with enable/disable toggles. Make sure your current file's language is set to 'true' (enabled). Alternatively, open Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and run 'GitHub Copilot: Enable for [language]'. Also check if there's a .vscode/settings.json in your workspace overriding global settings.
When to try: If status bar shows authentication warning or you recently changed your GitHub password
Open Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and run 'GitHub Copilot: Sign Out', then 'GitHub Copilot: Sign In'. Follow the browser authentication flow. This refreshes your auth token. If that doesn't work: go to github.com → Settings → Applications → Authorized OAuth Apps → revoke GitHub Copilot access → then sign in again from VS Code to get a fresh token.
When to try: If re-authenticating didn't help and status shows 'quota exceeded' or 'no access'
Go to github.com/settings/copilot (log in first). Check your subscription status. If it shows expired, payment failed, or 'no subscription', follow the prompts to renew. If you're on a company/org plan and lost access, contact whoever manages your GitHub organization — they may have reassigned your seat.
When to try: If you're on a corporate network or VPN
Test on a personal WiFi hotspot or disable VPN temporarily. If Copilot starts working, your corporate network or VPN is blocking Copilot's connections. Fix: in VS Code settings, set 'http.proxy' to your corporate proxy URL (ask IT for the value). Also add github.copilot.com and api.githubcopilot.com to your proxy/firewall allowlist. VS Code setting: http.proxySupport — set to 'on'.
When to try: If you have multiple AI coding tools installed
Open VS Code Extensions panel (Cmd+Shift+X / Ctrl+Shift+X). Look for other AI/autocomplete extensions: Tabnine, Codeium, Amazon CodeWhisperer, Kite, IntelliCode. Disable them one at a time and test if Copilot suggestions return. Multiple inline suggestion extensions create conflicts — pick one and disable the others.
When to try: If suggestions worked recently and stopped after a VS Code or extension update
In VS Code Extensions panel, find 'GitHub Copilot' and click the gear icon. Select 'Install Specific Version' to check if you're on the latest. If already current, try: right-click the extension → Uninstall, reload VS Code, then reinstall from the Marketplace. This clears any corrupted extension state.
When to try: For JetBrains IDE users
In JetBrains: go to Settings → Plugins → GitHub Copilot and ensure the plugin is enabled. Check Settings → Tools → GitHub Copilot for authentication status. Re-login if needed via Tools → GitHub Copilot → Login to GitHub. For suggestion trigger: default shortcut is Alt+\ (Windows/Linux) or Option+\ (Mac). Check if another plugin has overridden this shortcut in Settings → Keymap.
When to try: If Copilot works in other projects but not one specific repo
Some organizations disable Copilot on specific repositories. Check: github.com → your org → Settings → Code and automation → Copilot. If disabled for your repo, Copilot will show no suggestions only in that project. If you have owner access, you can re-enable it. If not, contact your org admin. You can also check in the VS Code Output panel — it will mention 'Copilot not enabled for this repository' if this is the cause.
Keep the GitHub Copilot VS Code extension set to auto-update — bug-fix releases ship frequently
Bookmark github.com/settings/copilot to quickly check subscription status when things break
If on a corporate network, set up the proxy config in VS Code once and document the settings for future reinstalls
Only enable one inline-suggestion AI extension at a time — disable others, don't just install them all
For team setups, use GitHub Copilot Business or Enterprise so admins control seats centrally rather than individuals managing subscriptions
Check githubstatus.com when Copilot stops working — GitHub outages affect Copilot since it relies on GitHub authentication
Contact GitHub support at support.github.com if: (1) Your subscription page shows active but Copilot still reports no access after re-authenticating, (2) You're on a Business/Enterprise plan and can't resolve seat assignment issues with your org admin, (3) You've tried all fixes and the VS Code output log shows persistent authentication errors with valid credentials. Also file a VS Code Copilot extension issue at github.com/microsoft/vscode-copilot-release if you suspect an extension bug after ruling out network and auth issues.
Three main causes for overnight stops: (1) Your authentication token expired — GitHub access tokens have limited lifespans and periodically need renewal. Fix: sign out of Copilot in VS Code and sign back in. (2) Your subscription payment failed — GitHub retries failed payments and then suspends access. Check github.com/settings/billing. (3) A GitHub Copilot extension update shipped with a bug. Check the Copilot extension changelog and downgrade to the previous version if there's a known issue. The VS Code Output → GitHub Copilot log will tell you which of these is happening.
Tab key conflict is the most common cause. Another extension is intercepting Tab before Copilot can handle it. Common culprits: Emmet (built into VS Code), TabNine, Prettier on-save, or any extension that maps to Tab key. Open Keyboard Shortcuts (Cmd+K Cmd+S / Ctrl+K Ctrl+S) and search for 'Tab' — look for conflicting bindings. You can also accept Copilot suggestions with Ctrl+Right (accept one word) or open Command Palette and run 'GitHub Copilot: Accept Suggestion'. Alternatively, try Copilot's alternate acceptance shortcut: Cmd+Right (Mac) or Ctrl+Right (Windows).
Check the GitHub Copilot icon in the VS Code status bar (bottom left). When Copilot is active for the current file, it shows a check mark. When disabled for the current language, it shows a strikethrough or different icon. You can also hover over the icon for a tooltip showing the current state. To enable for the current language: click the icon → 'Enable Completions for [language]' or open Command Palette → 'GitHub Copilot: Enable'.
No. GitHub Copilot requires an active internet connection to function — all suggestions are generated server-side by GitHub's AI models and sent to your editor in real time. There is no offline mode. If you're on a plane, working offline, or have a spotty connection, Copilot will either show no suggestions or show stale/delayed ones. For offline AI code completion, alternatives include locally-run models via tools like Ollama with Continue extension.
Language-specific enable/disable settings are the answer. Copilot stores a per-language toggle in your VS Code settings. Check Settings (Cmd+,) → search 'github.copilot.enable' → expand the object to see each language and its true/false toggle. Set your language to true. Also check your workspace's .vscode/settings.json — workspace settings override user settings and may have specific languages disabled for that project.
As of April 2026: GitHub Copilot officially supports VS Code, Visual Studio, JetBrains IDEs (IntelliJ, PyCharm, WebStorm, Rider, GoLand, CLion, PhpStorm, RubyMine), Neovim (via official plugin), and Azure Data Studio. GitHub has also released Copilot integration into GitHub.com itself (for PR suggestions and code review). Xcode and Eclipse support exists but is less polished. The VS Code extension is the most feature-complete and best supported.
GitHub Copilot is free for verified students, teachers, and maintainers of popular open source projects (apply at github.com/features/copilot). For everyone else: Individual plan is $10/month or $100/year. GitHub occasionally runs free trials. As of 2024-2025, GitHub added a limited free Copilot tier to all GitHub accounts with 2,000 code completions per month — check your github.com/settings/copilot to see if you have free access available.
Default shortcuts: VS Code on Mac: Option+\ to trigger inline suggestion; on Windows/Linux: Alt+\. To cycle through multiple suggestions: Option+] (next) and Option+[ (previous) on Mac, or Alt+] and Alt+[ on Windows. To open the Copilot completions panel showing all suggestions side-by-side: Ctrl+Enter (both platforms). If these shortcuts don't work, check Keyboard Shortcuts for conflicts with other extensions.
Copilot suggestion quality depends heavily on context. Common reasons for poor suggestions: (1) File is too new with no code context — add a comment describing what the function should do to give Copilot intent. (2) Unusual framework or internal library — Copilot was trained on public code, so proprietary internal APIs produce weaker suggestions. (3) Very large files — in files over 1,000 lines, Copilot may struggle to maintain context. Break files into modules. (4) Highly specialized domain (e.g., niche DSL) — use Copilot Chat and provide explicit context rather than relying on inline autocomplete.