Chrome throws ERR_PROXY_CONNECTION_FAILED when it cannot open a TCP connection to the proxy server configured in your browser or operating system. The target website is not contacted at all — the failure sits entirely on the hop between you and the proxy. This guide works through the causes in order of likelihood and ends with a one-command health check.
Chrome and other Chromium browsers (Edge, Brave, Opera) raise this error when a proxy is configured and the browser fails to establish a TCP connection to that proxy's host and port. DNS resolution of the proxy hostname may have failed, the port may not be listening, or a firewall may be blocking the route. Whatever the specific cause, the request never leaves for the target site.
Because the error concerns the browser-to-proxy hop, the site in your address bar is irrelevant: every site fails identically. That is the key diagnostic. If only HTTPS sites fail, you are looking at a different problem (see ERR_TUNNEL_CONNECTION_FAILED); if everything fails the same way, the proxy address itself is wrong, dead, or unreachable.
The most common real-world cause is not a broken proxy at all — it is a stale proxy setting. VPN clients, malware, 'web accelerator' utilities, and old debugging sessions leave system-level proxy entries behind, and Chrome inherits system proxy settings by default.
Work down this list in order — the first three steps resolve the large majority of cases.
10000 vs 1000) produces exactly this error.curl -x http://USER:[email protected]:10000 https://api.ipify.org. If curl succeeds, the endpoint is healthy and the problem is browser or extension configuration.nslookup residential.proxyomega.com. Chrome reports a failed proxy DNS lookup as ERR_PROXY_CONNECTION_FAILED, not as a name error.If you are running a proxy on purpose — for scraping, multi-accounting, or geo-testing — ERR_PROXY_CONNECTION_FAILED nearly always comes down to an endpoint detail: a dead endpoint from a free list, the wrong port for your plan, or an extension profile that quietly diverged from your dashboard settings.
ProxyOmega removes the most common variable: HTTP, HTTPS, and SOCKS5 are all served on the same port, so there is no protocol-to-port matching to get wrong. If curl connects through residential.proxyomega.com:10000 but your browser won't, the endpoint is fine — the browser-side configuration is what needs fixing.
Free proxy lists are the single biggest source of this error: endpoints go offline within hours of being published, and every browser configured against them then fails on all sites.
A maintained, authenticated endpoint — like the Budget Unlimited (/plan-unlimited/) rotating residential ports — turns 'is the proxy even alive?' from a daily question into a non-issue.
FoxyProxy and SwitchyOmega profiles override system settings silently, so an old profile pointing at a lapsed port keeps winning even after you fix the OS-level configuration.
Open the active profile and re-check host, port, and protocol against your dashboard — the walkthroughs at /integration/foxyproxy/ and /integration/switchyomega/ show a known-good setup.
If you never configured a proxy, something else did: an uninstalled VPN, a corporate policy, a 'free accelerator,' or malware pointing traffic at a server that no longer exists.
Delete the system-level entry rather than working around it in the browser, and scan the machine if the setting keeps reappearing.
Two commands settle whether the endpoint or your configuration is at fault. If both succeed, the proxy is healthy and every remaining suspect lives in your browser, extension, or OS settings.
# 1. Is the proxy port reachable at all?
nc -zv residential.proxyomega.com 10000
# 2. Does an authenticated request go through?
curl -x "http://USERNAME-country-us:[email protected]:10000" \
-sS https://api.ipify.org
# Prints the exit IP on success.
# Failure here = endpoint, credentials, or your network path.
# Success here + browser failure = browser or extension configuration.407 Proxy Authentication Required response or a login prompt — which requires a successful TCP connection first. ERR_PROXY_CONNECTION_FAILED happens earlier: the connection to the proxy never opens at all. Check the hostname, port, DNS resolution, and firewall rules instead of rotating passwords.One stable hostname, with HTTP, HTTPS, and SOCKS5 on every port — up and answering when you connect.
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