#Errors
Proxy error messages explained, with the cause behind each one.
14 articles
Java Proxy Authentication: 407 With the Right Password (disabledSchemes)
Why Java's HttpClient and HttpURLConnection get 407 from a proxy even with the correct login, and the one property that fixes it.
5 min read · #errors#authentication
Selenium Proxy With Username and Password (Chrome): What Works in 2026
Chrome under Selenium ignores a proxy login in --proxy-server and has no SOCKS5 auth. What each attempt does, and a local forwarder that works.
5 min read · #python#authentication
aiohttp Proxy Errors: ClientHttpProxyError 407, SOCKS5 and trust_env
aiohttp's ClientHttpProxyError explained, why its message leaks your proxy password, socks5:// without aiohttp-socks, and rotation.
6 min read · #python#errors
curl: (56) CONNECT tunnel failed, response 407 — and git's Proxy CONNECT aborted
What curl's 'CONNECT tunnel failed, response 407' means, every curl proxy exit code we hit, and why git fails through a proxy that works in curl.
6 min read · #errors#authentication
httpx: unexpected keyword argument 'proxies' — Fix Without Downgrading
httpx 0.28 removed proxies=. What replaces it (proxy= and mounts=), the OpenAI SDK case, SOCKS5 and environment proxies.
5 min read · #python#errors
Node.js fetch With a Proxy: undici ProxyAgent, NODE_USE_ENV_PROXY and Errors
Node's fetch ignores HTTPS_PROXY. Three ways to proxy it, the undici 8 'invalid onRequestStart method' trap, and where the proxy's 407 hides.
6 min read · #node.js#errors
Axios HTTPS Proxy Not Working: httpsAgent, proxy: false and 407
Why an axios proxy silently doesn't apply, why HTTPS_PROXY beats your agent, and how to tell the proxy's 403 from the website's.
6 min read · #node.js#errors
Playwright Proxy Errors: ERR_TUNNEL_CONNECTION_FAILED, NS_ERROR_PROXY_*
Every Playwright proxy error in Chromium and Firefox, what the proxy answered, the silent 30-second timeout on a wrong password, and SOCKS5 auth.
7 min read · #playwright#errors
Scrapy: Could not open CONNECT tunnel with proxy (407, 403, SOCKS5)
What the status in Scrapy's TunnelError means, why socks5:// only times out, and a proxy middleware that works. Every case reproduced.
7 min read · #scrapy#python
SSL: WRONG_VERSION_NUMBER With a Proxy: the Fix for Python, Go, Node and curl
The proxy URL says https:// and the proxy speaks plain HTTP. The same mistake and its error message in requests, httpx, Go, Node and curl.
6 min read · #python#go
Tunnel connection failed: 407 in Python requests (and 403, 465)
The status is the proxy's answer, not the website's. Five causes of 407 we reproduced, and what 403 and 465 mean instead.
7 min read · #python#errors
ProxyError: Cannot Connect to Proxy in Python requests: Every Cause
The message is a wrapper. How to read the exception inside it, each cause reproduced, and which errors are worth a retry.
7 min read · #python#errors
Missing dependencies for SOCKS support: the Fix, and Why You See It Without SOCKS
Install requests[socks], or find the environment variable that asked for SOCKS. Plus socks5 vs socks5h and the errors that come next.
6 min read · #python#socks5
Fixing ERR_TUNNEL_CONNECTION_FAILED in Puppeteer
Why the proxy refuses the tunnel, the two usual causes, and every other proxy error we reproduced in Puppeteer.
7 min read · #puppeteer#errors