Proxy troubleshooting
Selenium Proxy Not Working: Fix Capabilities, Auth and Browser Routing
A debugging guide for Selenium proxy setup in Chrome, Firefox and automated browser tests.
Fast diagnosis
If a Selenium proxy is not working, confirm the proxy works outside Selenium, then check WebDriver proxy capabilities, browser-specific options, authentication handling and whether the test browser actually receives the proxy setting.
Client
Proxy
Site
BuyProxies guide
Do not change five things at once. Test the proxy directly, then test the same proxy inside the browser, script or application that fails.
Symptoms you usually see
- Selenium launches but traffic uses the real IP.
- The browser opens a proxy auth prompt and the test stalls.
- Chrome works but Firefox fails, or the reverse.
- Requests fail with timeout or ERR_PROXY_CONNECTION_FAILED.
Most likely causes
| Cause | How to confirm it |
|---|---|
| Capability format wrong | Compare your settings with Selenium WebDriver proxy documentation. |
| Authentication prompt not handled | Browser-level proxy auth often needs extension or profile handling. |
| Wrong driver/browser option | ChromeOptions and Firefox profile settings differ. |
| Proxy itself failing | Directly test the proxy before changing Selenium code. |
Fix workflow
- Test the proxy in the Proxy Tester and a normal browser first.
- Use Selenium proxy capabilities exactly for the target browser.
- Avoid rotating the proxy during one browser session.
- Handle username/password auth deliberately instead of relying on a pop-up.
- Print the observed IP inside the Selenium session to confirm routing.
Field notes
Proxy errors become harder to solve when every layer changes at the same time. Keep the proxy, target URL, protocol and client constant until you know which layer fails. If the proxy fails in a simple direct test, the browser or script is not the first thing to fix. If the proxy works in a direct test but fails in the application, focus on application format, authentication handling, DNS behavior and whether another proxy/VPN setting overrides the request.
When debugging production jobs, save the exact proxy format, source machine, public IP, target URL, response code and timestamp. That small record is often enough to separate a temporary route failure from a repeated configuration mistake.
Useful checks
Selenium documents browser proxy configuration in its WebDriver docs: Selenium driver options.
Example debugging sequence
Start with one proxy and one target page. If the proxy fails in the tester, fix provider credentials, whitelist, port or protocol first. If it works in the tester, move to the failing application and copy the exact same host, port and authentication method. Then change only one variable at a time: first protocol, then credentials, then destination, then browser profile or script settings. This slower sequence is faster in practice because it avoids chasing false causes.
For teams, write the final working format into a short runbook. The next person should not need to rediscover whether the tool expects host:port:user:pass, a full proxy URL or separate username and password fields.
FAQ
Why does Selenium ignore my proxy?
The proxy may be attached to the wrong option object, overwritten by browser policy, or not passed to the driver session.
Can Selenium use authenticated proxies?
Yes, but authentication handling depends on the browser and driver approach.
Should each Selenium session keep one proxy?
For login or account tests, yes. Keep identity stable during the session.
Order clarity
What you receive
- What you receive
Proxy connection details for the package processed through the live order form.
- Protocols
HTTP or SOCKS5 options are shown during configuration for supported packages.
- Authentication
Set the requested proxy credentials during configuration before checkout.
- Locations
Current location availability is shown in the selector and can change with inventory.
- Support and checking
Support can help verify connection details and review replacement requests under the service policy.