ERR_TUNNEL_CONNECTION_FAILED Error

What the error means

To open a site over HTTPS, the browser asks the proxy to set up a “tunnel” to the site. If the proxy refuses, the browser shows ERR_TUNNEL_CONNECTION_FAILED.

Unlike ERR_PROXY_CONNECTION_FAILED, there is a connection to the proxy. The refusal came from the proxy itself: the credentials were not accepted, the site is closed or unavailable, or there is no address for the chosen geo.

Causes

• The proxy did not accept the username and password. The browser hides the 407 code behind a generic tunnel error.
• The site or port is closed for the proxy. For example, mail ports and sites from the list of blocked categories.
• The proxy could not connect to the site. The site is unavailable or rejected the connection from this address.
• No free address for the geo parameters. The country, city and ISP are too precise.
• The traffic has run out or the plan is paused. Then every request ends in a refusal.

How to fix it

1. Copy the proxy line from the dashboard again and enter the credentials once more.
2. Check the remaining traffic and the plan status.
3. Open another site. If the error is on one site only, the cause is that site: check the blocked sites page.
4. Simplify the geo: remove the city and ISP.
5. Retry the request: with rotation, the next one will go through a different address.
6. To see the exact cause, send the same request with curl using the -v flag — the response will contain the code and its name.

How to check that it works

The exact code is shown by the proxy checker or by the plan's request log in the dashboard. Then see the page for the matching error: 407, 403, 502 or 503.