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Troubleshooting network errors

When Foxglove tries to talk to a server that it can't reach, errors often come through with a generic "Failed to fetch" message.

Your browser intentionally hides the underlying cause for security reasons, so Foxglove can't tell exactly what went wrong.

If you encounter one of these errors, work through the following steps to troubleshoot the issue.

1. Check your internet connection​

Confirm that your machine is online and can reach the wider internet, or your internal network.

If you're on an unstable connection, a transient drop may cause a request to fail. Retry the request or refresh the page to try again. If the issue persists try disconnecting and reconnecting to the network.

2. Connect to your VPN​

If your organization hosts Foxglove, or uses a self-managed primary site, remote data loader, or remote files on your network, you may need to be connected to your corporate network through a VPN.

If you're unable to reach these services:

  • Make sure your VPN client is connected.
  • Ensure you can reach other internal services.
  • Reconnect the VPN if it has been idle, then retry the connection or reload the page.

3. Enable local network access​

When you connect to a device on your own network or through a VPN, your operating system and browser must allow Foxglove to reach the local network.

If you've been prompted to allow local network access, click Allow to ensure you can connect. If you've previously disallowed this setting, go to the site settings page in your browser for Foxglove and ensure the local network permission is set to Allow.

4. Check for a WAF or gateway login​

If your self-managed primary site, remote data loader or remote files sit behind a Web Application Firewall (WAF), proxy, or authentication gateway, requests can be silently blocked until you authenticate.

  • Open the gateway or SSO login page in a normal browser tab and sign in, then return to Foxglove and retry the connection or reload the page.
  • If a WAF is rate-limiting or blocking the requests, ask your infrastructure team to ensure Foxglove and your self-managed data is accessible.

5. Check the server's CORS configuration​

When you load a remote file by URL, it's served from a different origin than Foxglove, so the server must return the correct CORS headers. If it doesn't, the browser blocks the request and the remote file fails to open.

  • Make sure the server responds with an Access-Control-Allow-Origin header that permits the Foxglove origin (app.foxglove.dev, or your self-hosted domain).
  • Foxglove loads files using HTTP Range requests, so the server must also expose the range headers: include Accept-Ranges in Access-Control-Expose-Headers, and confirm the response carries an Accept-Ranges: bytes header.

Still stuck?​

If you've worked through the steps above and the error persists:

  1. Note the exact URL shown in the error details (expand the problem in the problems panel).
  2. Check your browser's developer console (Network tab) for failed requests and their status.
  3. Share these details with your infrastructure team, who can confirm whether the endpoint is reachable from your network, or reach out to Foxglove support.