Proxy error reference · Browser and client errors

ERR_PROXY_CONNECTION_FAILED: the browser cannot reach the proxy

Chromium network error: the exact message in each tool, the likely causes in order, and the fix that works.

Last updated: October 13, 2026 · 4 min read

Quick answer

What does ERR_PROXY_CONNECTION_FAILED mean with a proxy?

ERR_PROXY_CONNECTION_FAILED means the browser could not open a TCP connection to the proxy server, so no request left your machine. With CrawlRelay, check the gateway hostname for typos, use the right port for the protocol, and make sure no firewall, VPN or office network blocks outgoing connections to that port. Credentials play no part yet.

ERR_PROXY_CONNECTION_FAILED at a glance

Error	ERR_PROXY_CONNECTION_FAILED
Type	Chromium network error
Sent by	Your browser, which could not reach the proxy at all
Defined in	No HTTP status: the TCP connection to the proxy failed
Retry it?	No, until the proxy host and port are reachable
First check	Test that the gateway host and port are reachable from your machine

What does ERR_PROXY_CONNECTION_FAILED mean?

This error happens one step earlier than a tunnel error. The browser tried to connect to the proxy host and port and got no connection: a refusal, a timeout or a name that did not resolve. No proxy authentication took place and no website was contacted.

The cause is almost always local or on the path between you and the gateway: a typo, a blocked port, or a network that only allows web traffic on ports 80 and 443.

What does ERR_PROXY_CONNECTION_FAILED look like in Python, curl, Node.js and browsers?

The same failure prints differently in every tool. These are the messages to search your logs for:

Chrome: 'No internet' page with ERR_PROXY_CONNECTION_FAILED
Playwright: page.goto: net::ERR_PROXY_CONNECTION_FAILED at https://...
Puppeteer: Error: net::ERR_PROXY_CONNECTION_FAILED at https://...
Non-browser clients: Connection refused, timed out or a name-resolution error on the proxy host

What causes ERR_PROXY_CONNECTION_FAILED?

Most likely first:

A typo in the gateway hostname or a missing port.
The wrong port, such as an old port from another provider.
Outbound filtering: office, school and some hotel networks block uncommon ports.
A VPN or local security software that intercepts outgoing connections.
DNS problems on your machine or network.

How do I diagnose ERR_PROXY_CONNECTION_FAILED step by step?

Resolve the gateway name: nslookup followed by the host.
Test the port: on Windows, Test-NetConnection with -Port; on macOS and Linux, nc -vz host port.
Run the curl test below from the same machine.
Try another network, for example a phone hotspot, to rule out a local block.

Test the failing URL with curl (HTTP port, verbose)

# Use the URL that fails; with https://api.ipify.org instead, you test the gateway alone.
# "HTTP/1.1 200 Connection established" first, then the site's own status: the site answered.
curl -v -x http://USERNAME:[email protected]:7777 https://TARGET_URL

# Same test through the SOCKS5 port, with DNS resolved at the exit
curl -v --socks5-hostname gw.crawlrelay.com:7778 --proxy-user USERNAME:PASSWORD https://TARGET_URL

How do I fix ERR_PROXY_CONNECTION_FAILED?

Copy the host and port straight from the dashboard instead of typing them.
Allow outbound traffic to the gateway port in your firewall, or ask your network admin.
Pause the VPN while testing, or exclude the gateway host from it.
On servers, check cloud security-group rules for outbound connections.

Should I retry after ERR_PROXY_CONNECTION_FAILED?

Do not retry in a loop: nothing changes until the network path is fixed. Run the reachability checks once, fix the cause, then start the browser again.

How does ERR_PROXY_CONNECTION_FAILED apply to CrawlRelay?

CrawlRelay's gateway uses one port for HTTP and one for SOCKS5, both listed below; browsers should use the HTTP port. If your network allows outgoing traffic only on ports 80 and 443, run the scraper from a server or from another network.

Gateway: gw.crawlrelay.com, port 7777 (HTTP, HTTPS through CONNECT) and port 7778 (SOCKS5). Username format: USERNAME-country-{cc}-state-{state}-city-{city}-zip-{zip}-asn-{asn}-session-{id}-ttl-{minutes}. Related: ERR_TUNNEL_CONNECTION_FAILED · Cannot connect to proxy · Quick start.

ERR_PROXY_CONNECTION_FAILED: questions developers ask

What is the difference between ERR_PROXY_CONNECTION_FAILED and ERR_TUNNEL_CONNECTION_FAILED?

ERR_PROXY_CONNECTION_FAILED means the browser could not reach the proxy at all. ERR_TUNNEL_CONNECTION_FAILED means it reached the proxy, but the proxy refused or failed to open the tunnel to the website. The first is a network path problem; the second is usually credentials or the target.

Can a firewall block my proxy connection?

Yes. Many company and school networks allow outgoing web traffic only on ports 80 and 443 and block other ports. A proxy gateway on a different port then fails with a connection error. Test from another network, or ask the network administrator to allow the port.

Do I need to whitelist my IP to use the gateway?

No. Username and password authentication works from any IP address, so a new home connection or a new server needs no change. If the connection still fails, the problem is the network path: a typo, a blocked port or a VPN, as described above.

Other proxy errors in this reference

HTTP status codes

Browser and client errors

Connection and TLS errors

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