Firefox: "The proxy server is refusing connections" explained

Updated: 2026-11-07

"The proxy server is refusing connections" means Firefox reached the proxy address and the machine there replied that the port is closed to connections. Because this happens before any username or password is exchanged, changing the login will not help. The cause sits in the address, the port, or the Firefox setting that points to them.

HTTP(S) proxies that drop straight into Firefox

See live prices Free Proxy Checker

Common reasons Firefox gets refused

A local proxy app was closed. Debugging tools and proxy apps often listen on 127.0.0.1. Quit the app while Firefox still points at it and every page is refused.
Firefox inherits the system proxy. With "Use system proxy settings" selected, an outdated proxy in Windows or macOS breaks Firefox as well.
Wrong port, or an order that is no longer active. The port in Firefox does not match your order, or the proxy no longer serves on it.
Wrong field in the dialog. An HTTP proxy entered under SOCKS Host, or the reverse. ProxyV4 proxies are HTTP(S), so they belong in the HTTP Proxy field.

Test the port yourself

Firefox offers no detail beyond the message, so ask the port directly. Pointing curl at the documentation address 203.0.113.10:8080, where no service was running, produced curl: (7) Failed to connect to 203.0.113.10 port 8080 after 0 ms: Couldn't connect to server. Note the after 0 ms. A refusal returns almost immediately, while a proxy timeout keeps you waiting because nothing answers.

Without a terminal, the proxy checker reports this case as connect failed, and the port checker tells you whether the port can be reached from the internet. Chrome and Edge describe the identical failure as ERR_PROXY_CONNECTION_FAILED.

Correct the Firefox connection settings

Option in Firefox	What to do
Where to find it	Open Settings, scroll down to Network Settings and press its Settings button.
No proxy	Pick it if you do not need a proxy and press OK. If the pages load now, the old configuration was to blame.
Use system proxy settings	Firefox copies the operating system. Fix or remove the proxy there; the turn off proxy guide shows how.
Manual proxy configuration	Compare every field with your order in the dashboard. Put an HTTP(S) proxy in HTTP Proxy with its port, and leave SOCKS Host empty.
Login prompt	For a password-protected proxy, Firefox asks for username and password on the first page load. More in Firefox proxy setup.

The same refusal in other tools

In antidetect browsers a closed port usually shows up as a proxy check that fails instantly. In Python, requests raises requests.exceptions.ProxyError for problems connecting to the proxy; print the whole message to see the underlying reason. Whatever the tool, the remedy is identical: confirm the IP and port against your order, then confirm the port is open.

Step by step

1
Open Network Settings in Firefox
Settings > Network Settings > Settings shows which proxy mode is active.
2
Switch to No proxy as a test
Choose No proxy, press OK and reload, to see whether the proxy setting causes the refusal.
3
Check the proxy's port
If you need the proxy, run the line through the proxy checker or curl -x and look for error (7).
4
Enter it again in HTTP Proxy
Type the IP and port from your order into the HTTP Proxy field, save, and open a test page.

Frequently asked questions

Can a wrong password cause a refused proxy connection?

No. The refusal happens before any login. A bad password produces a 407 error or a login box that keeps coming back.

I never configured a proxy, so why does Firefox say this?

Check whether Firefox is set to use the system proxy, then look at the operating-system settings and at any proxy add-ons installed in Firefox.

Why does the proxy work in Chrome but not in Firefox?

Firefox can keep its own proxy configuration separate from the system. Open Network Settings and compare the IP, port and field with what Chrome uses.

It only fails on the office network.

That network may block outgoing connections to some ports. Try the same proxy on mobile data; if it works, ask the network administrator. See checking the proxy and the firewall.