ERR_TUNNEL_CONNECTION_FAILED — What It Means & How to Fix It

What Does This Error Mean?

ERR_TUNNEL_CONNECTION_FAILED means your browser tried to create a secure tunnel through a proxy server to reach an HTTPS website, but the tunnel could not be established. When you visit an HTTPS site through a proxy, the browser first sends a CONNECT request to the proxy asking it to set up a secure tunnel. If the proxy refuses or cannot reach the destination, the tunnel fails and you see this error.

Affected Models

Google Chrome
Microsoft Edge
Chromium-based browsers
Windows
macOS

Common Causes

Your proxy server does not support the CONNECT method required for HTTPS tunneling
The proxy server's access control rules are blocking the destination website
The proxy settings in your browser or Windows point to an incorrect or outdated server address
A VPN app left incorrect proxy settings after being disconnected or uninstalled
The destination website's port (usually 443) is being blocked by the proxy or firewall

How to Fix It

Check and clear your proxy settings. In Chrome, go to Settings > System > Open your computer's proxy settings. Under Manual proxy setup, turn off 'Use a proxy server'. Click Save.

If no proxy is needed, turning it off completely will fix the error immediately.
If you are on a work network that requires a proxy, verify the proxy address and port number with your IT department. An incorrect address will cause this exact error.

Proxy settings are formatted like: proxyserver.company.com:8080
Disconnect from any VPN and check if the error clears. Some VPNs set a local proxy and may malfunction, causing tunnel failures.

If the error disappears after disconnecting the VPN, try reconnecting to a different VPN server.
Reset Internet Explorer/Windows proxy settings. Press Windows+R, type inetcpl.cpl, go to Connections > LAN Settings, and uncheck 'Use a proxy server for your LAN'.

Chrome uses Windows' proxy settings by default. Clearing them here clears them for Chrome too.
Try accessing the site without the proxy by connecting to a different network — such as your phone's hotspot — to confirm whether the issue is proxy-related or site-related.

If the site loads fine on mobile data, the proxy on your main network is the problem.

When to Call a Professional

If you are on a corporate network, your IT department manages the proxy. Report the error and the specific site you are trying to reach. If you manage your own proxy server, check that CONNECT tunneling is allowed in the proxy configuration.

Frequently Asked Questions

What is a CONNECT tunnel?

When you visit an HTTPS website through a proxy, your browser sends a special 'CONNECT' command to the proxy. This tells the proxy to open a direct tunnel to the destination server. All the encrypted HTTPS traffic then flows through that tunnel. If the proxy cannot or will not create that tunnel, this error appears.

Can this error appear even without a proxy set up?

Rarely, but yes. Some corporate network security equipment acts like a transparent proxy — intercepting your traffic without you explicitly configuring a proxy. If you are on a work or school network and see this error on personal devices, the network itself may be acting as a proxy.

Is ERR_TUNNEL_CONNECTION_FAILED the same as ERR_PROXY_CONNECTION_FAILED?

They are related but different. ERR_PROXY_CONNECTION_FAILED means your browser could not reach the proxy server at all. ERR_TUNNEL_CONNECTION_FAILED means the proxy was reached, but when your browser asked it to create a secure tunnel, the proxy refused or failed. Both usually come down to incorrect or broken proxy settings.