Getting ERR_PROXY_CONNECTION_FAILED? Here’s why it happens and the exact fix.
You are seeing ERR_PROXY_CONNECTION_FAILED because your client cannot establish a TCP connection to the proxy gateway. The fix: check your proxy endpoint address, port, and ensure your firewall allows outbound connections on the proxy port.
Check gw.knoxproxy.com:7000 for residential and dc.knoxproxy.com:8000 for datacenter against your dashboard.
Run: telnet gw.knoxproxy.com 7000. If it connects, the network path is clear.
Run: nslookup gw.knoxproxy.com. Verify it resolves to an IP address.
Allow outbound TCP on ports 7000 and 8000 to gw.knoxproxy.com and dc.knoxproxy.com.
import requests
# Correct port: 7000 for residential gateway
proxy = "http://USER:PASS@gw.knoxproxy.com:7000"
r = requests.get("https://httpbin.org/ip", proxies={"https": proxy})
print(r.json()) # {"origin": "residential-ip"}Test your setup with our proxy checker, then contact support if ERR_PROXY_CONNECTION_FAILED still won’t clear.
ERR_PROXY_CONNECTION_FAILED means your HTTP client attempted to connect to the proxy server but the TCP handshake failed. The request never left your machine. This is a local network or configuration issue -- the proxy gateway is unreachable from your client. Common in corporate networks with restrictive firewalls, misconfigured proxy URLs, or when using the wrong port.
Use the exact endpoint from your dashboard: gw.knoxproxy.com:7000 for residential, dc.knoxproxy.com:8000 for datacenter.
Allow outbound TCP to gw.knoxproxy.com on ports 7000 and 8000 in your firewall rules.
Check your DNS configuration. Try using 8.8.8.8 or 1.1.1.1 as DNS resolvers.
If connectivity tests pass but your application still fails, the issue may be in your HTTP library proxy configuration. Contact KnoxProxy support with your library/language and proxy URL format.
From your machine. ERR_PROXY_CONNECTION_FAILED means your client could not reach the proxy. The proxy never received your request.
Your server likely has a firewall that blocks outbound connections on non-standard ports (7000, 8000). Add firewall allow rules for the proxy ports.
KnoxProxy gateway ports are fixed: 7000 for residential, 8000 for datacenter, 9000 for ISP. You cannot use custom ports. Ensure your firewall allows these specific ports.
KnoxProxy comes pre-configured to avoid the most common errors. Start a free trial and fix ERR_PROXY_CONNECTION_FAILED for good.